I have an iPad 8 32gb, fully up to date, and I have the Photoshop app for it. After a bit of drawing, it notifies me that it was unable to save my work, which is followed by my iPad telling me that my storage is full. But when I check my storage, the storage use says ~25gb used, then jumps down to 23gb after a minute. I have 10gb space free yet it seems like photoshop keeps doing something to momentarily fill up all of that free space when in use. Help?
It sounds like you're exceeding the Scratch Disk requirements of your file. Unfortunately, there is no setting for scratch disks on the iPad version of Photoshop.
You could try creating the same image at the same settings with the desktop version whle monitoring Scratch Sizes at the lower left of the document. Scratch Sizes displayed at the lower left of a Photoshop document.
This will give you and idea of what's needed when you're working with a similar file on your iPad.