I use my Poke3 like a work horse and haven't had any problems.
So, are your problems due to corruption of system components that are read-only?
Is it due to bad configurations in the read-write userdata (/data)?
The last update (maybe really the last) was ONYX/Poke3/Poke3:10/2022-11-25_04-32_3.3.1_4c98746d8/7996:user/dev-keys
You might just do an "update" over the same version.
Updates don't disturb your userdata.
You'd need
http://firmware-us-volc.boox.com/3b9...06a/update.upx
You'd need to decrypt it using
https://github.com/Hagb/decryptBooxUpdateUpx
You could install it with my custom recovery (not saying that there couldn't be other ways).