I found out about Warframe after playing DarkSector and hearing that the two were related. The reviews seem generally positive with the exception of one massive negative spike.
Is there much in the way of grinding and micro transactions?
Unlikely, the warframe community for Linux is pretty large. I even remember the Nobara discord had a channel just for warftame. I’ve been playing warframe for over a year on Linux with no issue. The ban is likely unrelated to proton.
The first versions of Proton-GE were made by GloriousEggroll specifically to get Warframe working, some other games just happened to be playable because of the same tweaks/fixes needed.