Should I use which file system for Proton and Wine prefixes on Lutris or Steam with an external SSD or microSD card under SteamOS ?
In the Bazzite documentation says “FAT32 and exFAT are unsupported . Both filesystems do not support symbolic links which is required for Proton prefixes to work properly. However, there are scenarios where a microSD card is formatted to exFAT may work in some cases, but this method is unsupported as something the Bazzite maintainers do not plan to accommodate.”
Ext4 will be the easiest probably. The deck supports BTRFS, but requires manual remounting after every steamOS update for some reason.
If you do want to use BTRFS, I’d look into Popsulfr’s deck BTRFS project. I know it can auto configure microSD cards for BTRFS (and fix the previously mentioned mounting issue), as well as set up some of the other BTRFS benefits like automatic compression and deduplication. Deduplication especially can save you a lot of space.
BTRFS compression can also speed up load times when loading games from slower storage like a microSD, which is a nice benefit to go alongside the increased storage space.