There has never been a "backup" button. The only way you can make "backups" is to use
.config save (name)
Are you talking about world backups, if you try running a world? Image below:
It could be due to outdated files. It's also not a launcher that we officially support
You could try deleting /storage/emulated/0/Android/data/net.kdt.pojavlaunch/files/.minecraft/libraries/me/deftware/EMC/latest-1.12.2/EMC-latest-1.12.2.jar
Or using the Forge version instead
It has not worked at all since 1.19, so this is not possible unless you were using cracked servers. The method used for authenticating the token no longer works since chat reporting features were added to the game, and the devs have not added any sort of workaround to this.
It cannot, has not, and will most likely never work past 1.18