Looking at the backup methods on https://retropie.org.uk/docs/Updating-RetroPie/ I think the best one for me in this situation is to backup the bios, configs, and roms directories via the samba shares. However, assuming the update works perfectly, which of these directories should I copy back over to preserve my roms, save states/files, and configurations (like controller configs and core-level configs). I'm assuming just the roms and configs directory and that I should not copy bios back over to the new image, but I wanted to check and be sure.
as the docs says, you'll want to backup all 3 https://retropie.org.uk/docs/Updating-RetroPie/#backup-option-2
By installing from source and now doing a new image install, am I nuking my micro-sd card with writes? I have no idea how many writes an install from source does, but it took hours to finish.
it's not ideal but during development i do many days worth of rebuilds and my SD cards tend to last years before crapping out.