I should have configured to use internal memory when I had the chance (the time it worked right after the factory reset. As you can see from the screenshot, when the failure happens, the button to change the storage location is not availiable. I will definately re-submit a bug report.
The SD card is not set as part of the internal storage - I think that option went away on Android 10? It could be a failing card, but the card is still working fine for media (music, pictures, etc.) - maybe i will remove it and test it in my PC since the failure may be a weird one. One thing i have learned playing with raspberry pis is that weirdness is almost alyways caused by a flakey SD card.
I am on Android 11. There was an android update that happened on my phone a couple weeks before I started having this problem, but I dont know if that was directly related.