i really think this is mostly a nothing burger

you listed a bunch of consequences for this situation, but most of them are avoidable or not that impactful or important:

1) don' trade using energy and you won't feel the inflation
2) the only loss in value happens if you try to convert energy into crowns
3) that's like saying someone bought an expensive pair of shoes a month ago and since they are now 50% off in the store, it's bad for them. sure it sucks, but you can't expect the game to preserve the value of your items in perpetuity.
4) always found it weird that people used two currencies at the same time for trades. most other mmos that come to mind do not do this. energy is fine the way it is as the utility currency for special unbinds, progression helpers, sparks of life, etc.
5) people will no longer trade each other using energy. why is that bad? this is amazing. if the game ever gets an influx of new players, just think about how easy it will be for them to get more energy for the alchemy orbs they need to pass the grind walls in the game. love it for them
6) "this is bad because scammers exist" report them, ask the help of a gm, make sure you stay informed, help inform others. nothing new here
7) people always try to get better deals from themselves. this was always the case, even with more valuable energy, nothing has changed. in fact, it will get easier going forward if people only use 1 currency in trades, no more conversions needed

tldr: i believe game would be healthier if players only traded between each other in a single currency, one for which you have to play the game to obtain rather than spend real money or buy one currency, wait for conversion prices to shift in your favor, convert for profit, repeat.

energy is just as valuable as before and just as useful as before to get sparks, orbs, crystals, unbinds and whatever else your heart desires from the depot.

I find this situation fascinating because I've been playing this game off and on (a big chunk of off until recently) since 2011, and the only money I've ever spent on it was to buy OCH. I've never once bought disposable premium currency for a game, and I have no plans to ever do so. It's just...completely against my nature. So in that context as someone who only rarely buys things from the AH, doesn't roll for UVs unless I get a free forge box ticket, and could not care less about pretty cosmetics, this situation has been fantastic. I've made a few recent Depot purchases I never would have otherwise (new battle sprite!), and despite usually resisting it and waiting for luck to strike I'm almost at the point where I may start throwing energy at orbs occasionally. I get that at its core the game requires someone to be spending real money in order to keep functioning, and I'm very grateful to the collective playerbase that does so, but given how far I've seen the energy market skewed in the other direction in the past this feels pretty good.

(Now if GH really wanted to get my money, they'd offer a few permanently-obtainable things for it. Like if they woke up tomorrow and said "here, how about $5 for a permanent third weapon slot unlock"? I'd do that in an instant without thinking twice.)

What you're identifying right now is the same thing that happened when the game rereleased as a Steam game. It's a good thing. It means blood is pumping and there are efforts to grow the game instead of just wring out anybody left attached to it. I'm personally very pleased even though my pile of energy I set aside years ago in case a friend ever wanted to play this game but didn't want to fight the microtransaction hellscape it became is now worth thousands of less crowns at today's prices than when I'd put in the buy orders for it.

Spenders keep the lights on. Spenders are the people buying energy today because they already find the current price acceptable to them, which the existing bubble could not have predicted because it was predicated on several years of GH not doing anything to develop the game and exclusively catering to its existing userbase of a few big spenders and sterling representatives of the free, info-blind market (scammers).

Speculative, hoarded wealth in a game where money prints itself is fundamentally volatile, and so only items that are completely exclusive to realworld direct purchases are 'protected' from the actions of the playerbase regarding crowns generated and CE purchased. I have no pity for people whose inventories got devalued by falling CE prices in the same way I try not to blame anyone for selling things at exorbitant prices when CE was more expensive. It's how the system was originally meant to work, where paying players subsidize free players and vice versa. Right now, the game is being made more welcoming to new or returning players by the actions of the new and returning players actually playing Spiral Knights instead of primarily using it as a trading simulator with a fashion show and game attached to it vestigially. An excellent development, courtesy of GH advertising stuff and things of vague intent are in the works on the gameplay side of the equation.

There are no shortage of crown sinks what with UVs and slime lootboxes (also guildhall upkeep but that has very little gameplay impact), both addictive gambling with extremely high upper boundaries. Featured auctions also sink crowns for more cosmetically-inclined players. The blindspot for CE right now is a lack of Supply Depot specials, where the prices for cosmetics relative to real-money-to-CE have usually been absurd as they're proportional to their original acquisition rates from the boxes they came with, if they were previously released that way. It would be nice if there were more depot listings to revive those items - which would raise the prices of energy which I personally don't like, but would make them far more healthily available since depot purchases are completely consistent, no gambling involved.

The removal of mist energy did not uncap gameplay. You could continue to play and earn money despite paying for the elevator costs so long as you were committing to runs to get to deeper floors, selling your materials from underplayed stages (esp. Monster Bones and Green Shards because crafting was the only means of generating UVs), or slaving away in the highest paying floors. Your value of time to gameplay was actually improved by mist energy, where you were guaranteed to be making progress no matter how you spent it since anyone playing in excess was being gently taxed. Raw crown output trended toward the highest-paying stages; material worth trended toward the crowns in circulation just like it did with CE; and CE was occasionally bundled as a bonus from purchasing paid cosmetics. Elevator passes existed as a subscription middleground between the existing microtransaction walls and playing the game. It was a very nice setup where no matter what you did, your time was worth something. There were other little things involved that greased it too, like tier latejoin fees and the like... Still, it would've been nice if the mist cap was higher; say 200 rather than 100.

In terms of the hours you spent playing the game, the original system was restricted grind with consistently fast progress, and what we have with the Forge is infinite grind with consistently slow progress. CE prices utterly exploded when mist got removed and were more susceptible to rigging with no such farming clamps and with the addition of direct crown-to-UV trades via Punch, alongside rarities, missions, and the like. You could now grind indefinitely with no upfront tax (a very effective trojan horse change) - and in exchange you have to grind far more than you would've in terms of game time. You could spend 7 hours over 7 days previously or 7 hours in 1 day today and still be playing the same number of levels, but in the latter's case we have an environment where inflation has no brakes and crafting costs were generally sharper because it was no longer possible to buffer 100 CE's worth of crafting costs with mist and orb droprates are low enough that playing early stages is not more efficient than playing the highest-paying T3 stages that can convert crowns to CE to buy them from the depot directly... Even today's CE prices are contextually less favorable despite being similar to the ~3k the game had on release and on Steam rerelease.

I think the forge box changes were brilliant. An excellent move! The unused orbs from longtime players can now be used for UV-chasing just like the pre-Punch days of yore, which is driving material prices up for desirable items, and because the primary rewards from forge boxes are UV tickets, this serves as gentle equalization between energy and crowns beyond vendor prices. A strong balance patch that improves a lot of the game's underperforming or worthless equipment to encourage the creation of more gear would have beautiful synergy with this. Turbillion is a fine weapon numerically and one of the few nice things GH's done on the gameplay side since its reacquisiton, and all they had to do was tune its stats and give it a new model! They didn't even have to fix its still-malfunctioning terrible charge attack. I wish they would, though.

Knowing how all of these systems work, it's a miracle the game's so quickly returning to healthy shape economically, and it's proof that SK always could've been something if only something had been done with it.

EDIT: ... and now there's a Rage prize box, not Rage items directly, in the depot. Oh well. So much for things looking up.

Fallen made a valid Point and another player said that Promo boxes being better on real currency over Energy packs could force the Energy hoarders to get rid of it instead of Just pilling...(this could backfire, but extend the Low rates and they'll have to move the Energy, because demand wont stop)

I exist in a similar position to Vyre at this point. I've already gotten most of what I want that would cost me real money. I got my dream costume. I have all of the reasonably acquirable "good" weapons. At this point, the only thing left for me to spend on is messing around with more gimmicky or just bad gear. I just play for the sake of playing now, although it's always nice to get the "number go up" dopamine hit when looking at my crown count.

Merchants seem to be playing a completely different game from the rest of the playerbase. Feels like when someone reaches the "endgame" they either start trying to do trading and focus on money or just start collecting gear or even just quit since there's nothing else to do. A lot of people just don't care for the whole "economy" shtick and so they just putter around with nothing to do and nothing to buy other than the few cosmetics they genuinely want to use.

Supply depot listings may placate your needs for now, but how will the new players feel when they have to watch the price of energy rise in real time? A surge in energy prices could very well cripple the effort to revive this game. Just because it's been years since energy was 10kcrs doesn't mean it can't happen again and a huge surge of new players flooding the market with more crowns than ever before will cause that pretty fast I'd think. This market is more headache than it's worth.

edit: forgot to bring this up but I feel like even as a progressing player crowns don't hold much worth to me. It's always cheaper to buy orbs via depot than it is AH. Energy was always my go-to when I was progressing, even if a majority of stuff offered there was overpriced (700e for 50 radiant crystals or $10 for a 5* gear good lord). What are crowns used for that a new player would engage with? Recipes are really the only thing that comes to mind. Not much else is really worth even buying on AH. Materials have been a non-issue to anyone not looking to rage craft ever since missions were introduced. Maybe the occasional orb if I'm really really impatient. No sane person blows crowns in a mission lobby for a vitapod or some junk like that. Crafting costs are negligible.

If anything I think crowns hold too little value to the average player, not energy. It's only once we hit endgame that our demand would theoretically skyrocket and that entirely hinges on us perceiving UV gambling or cosmetics as worthwhile ventures which many don't. When allowing us to trade between two types of currency, we'll need to constantly try and balance their value by surgically messing with the things they're used for. This is just a lot of unnecessary work.