Use syncthing and just sync all your important folders!
On F-Droid app store use Syncthing-forked
https://f-droid.org/en/packages/com.github.catfriend1.syncthingfork/
There are probably other more wholistic and specific ways to do this with apps specifically designed for it, but Syncthing you can use for pretty much anything and any other internet connected device you have you can use Syncthing to share/backup files too.
You don't even need internet to use Syncthing, it will work entirely over your local network if both devices are on the same network.