The game does use nProtect anti-cheat but that seems to run just fine under proton despite not technically being supported. This condition might change so buyer beware, but considering that steam is pushing proton patches for the game I would assume that Arrowhead intends to leave linux compatibiltiy alone.

I actually consider this to be a better condition than on windows since nProtect is a kernel level AC and it cant do anything with the linux kernel through proton so you are a bit safer from some of the hardware issues reported on windows and from the obvoius rootkit issues all kernel level ACs bring up.