In general, the best way to play unsupported games on Linux is through a VPS with gpu-passthrough and if you want to set that up maybe look for guides in /r/vfio
I did this once and managed to set it up, it worked pretty good with barely and notice in performance loss, in every game I tried expect Tera 
Since Tera is primarily CPU bottlenecked it ran pretty shitty compared to natively on my pc. It worked fine if you disabled the UI though. There may be better ways to optimize cpu usage in QEMU but I didn't have that expertise so I just gave up
The game does work pretty fine with Wine though, if you want to try that
EDIT: If you run the game on Steam, steam has their own wine project called Proton that lets you run games which is way easier to run than manually configuring wine to work. Try that
