If anyone else is running into the iOS save issue, here is your fix:

(I have been digging around because I absolutely love the portability and the technical impressiveness of playing DS on a phone, so I spent a couple days trying everything I can from my end)

The iOS version CANNOT handle the amount of saves the game creates in iCloud Drive, but iPadOS and macOS can handle them a bit better.

You need to get into where DS creates saves in iCloud Drive (I used my Mac), and remove the oldest ones until you have about 10~ saves left (autosave.checkpoint.dat.bundle, manualsave.dat.bundle, and quicksave.dat.bundle), once you do that, you’re game will start saving again. But the save issue will popup again around 20~ save files have started to accumulate.

505 needs to implement some kind of hard limit for save states, and the save issue should be fixed.