Something you may need to consider:
An iOS device - yours - has a single user, instead of [every-day] multiple user accounts.
The iOS file system therefore includes various assumptions.
One assumption, is that YOU are the owner of various directories. File and folder permissions are either YOURS, or various iOS default owners (root, etc. - too much jargon, here).
If something -— LIKE GOOGLE -— manages to change the owner of a directory, to an un-authorized or un-expected name, then YOU may not be able to store items to that directory . . .
AND GOOGLE WILL.
Is one possibility.
IOW, something may have tampered with some tidbit(s) of your iOS File System.
Unfortunately, there is no *Disk First Aid* (such as for the Mac OS) . . . for iOS.
Given that you probably have a lot of valuable images and other files on your iPad, try to save that data to some hard drive via your iPad’s “parent” computer.
Be prepared. In order to run a complete RESET of your iPad -— as in restoring it to factory condition, followed by upgrades, followed by your laboring at adjusting the settings.
Whether or not that sounds appealing, at least be prepared and back up your files.
Good thought. I will.