Basically to solve your problem of having the rich kats with 50k ce or more never having to spend another cent on the game. Just put in any hard CE dump.
For example make it so once you get a item to level 10 you can re-roll the UV, which resets it to lvl 1 and has a lower chance than normal crafting UV, has a higher CE cost and still uses the same mats. This works in 2 ways, one its a hard ce dump and it also is a heat dump meaning there is something for the people who have done everything. It will also lower the cost of UVs, making it so this system doesn't make people insanely rich, and people will still spend money on the game.
Or some mini-games, like lichen soccer, which costs CE to play and can win cool prizes.
One more thing, remove the crafting changes, the binding of 4* and 5* and increased cost is just stupid. Yes it does allow people to come into the game, spend a little bit of money and get straight into the endgame, but hey! they're still giving you money.
Theres my 2 cents.
I don't think anyone would do that. It's still cheaper to mass UV craft low level items to get the UV you want instead of rolling at 800CE+ per roll with less chance of UV.