So Radiants were banished to the very last depth of the very last mission because they overwrote Shining drops. But the same patch that did this added Fire Crystal downcrafting to let people turn the abundant Radiants into Shinings.
Soooooo...
OOO added a fix, but made it obsolete at its creation, and even REVERSED the situation by making radiants exceedingly rare?
Come on. Just use your noggin for a moment. This is silly.
Bring the Radiant drops back up. They're much too sparse. We can craft them into shinings now, so there's no reason to make shinings prioritize them. Heck, Radiants could fill all of Tier 3 considering you can downcraft them.
Getting a 5* item to even just level 3 is an absolute chore.
Personally, I think a better fix would just be to make all these things completely based on stratum.
That is to say, only one kind drops per stratum, and it's what you need to get to the next one.
Stratum 1: 0* equipment, find cracked crystals, find flawed orbs.
Stratum 2: 1* equipment, find dim crystals, find simple orbs.
Stratum 3: 2* equipment, find warm crystals, find advanced orbs.
Stratum 4: 3* equipment, find glowing crystals, find elite orbs.
Stratum 5: 4* equipment, find shining crystals, find eternal orbs.
Stratum 6: 5* equipment, find radiant crystals, find eternal orbs.
So instead of trying to figure out the exact depth to play to get whatever thing, just play something in the right stratum.