Android’s stock backup misses a lot of things, apps can opt-out and many do, it also doesn’t backup files or documents or photos. Photos are “backed up” if you enable Google Photos cloud sync, but that’s separate. It basically just backs up your phone calls/SMS, system settings and what apps you have installed (but not their data unless they tie into the backup APIs).
According to this twitter, the data partition needs an fsck: https://twitter.com/MishaalRahman/status/1721945205119553794
And people have tried the Nov OTA image, it didn’t help: https://issuetracker.google.com/u/1/issues/305766503#comment843