I haven’t actually touched selinux at all… It’s not ‘officially supported’ in Arch yet, although there are compatible packages available. I only recently discovered PAM which I have yet to learn too.
Note that there isn’t a Linux version of the protondrive app. … I know! what the fuck right?
Secondly, I would just shove Linux Mint onto a USB and use that as a live distro with persistence for a while, just to get used to things. I’m not a fan of debian(/-based) or apt, but it works.