@mimattr: Can confirm. Same here. Xubuntu 18.4, GTX 970, Driver Version 396.54, i7 6700K, Proton 3.7-6 (Beta).
Bad Blood seems to run well but Easy Anti-Cheat kicks me out of the matchmaking after one or two minutes.
VSync don't really works but with Nvidia option "Force Full Composition Pipeline" it runs smoothly. I also think I have noticed small soundbugs, but hardly noticeable. I'd have to play it for a while to test everything, but it's difficult because of EAC. I think the EAC problem has to be solved in Wine because it also affects games outside Steam. Games on Steam might use VAC as an alternative in future.
proton 3.7-6x1 2018-09proton 3.7-5x1 2018-09
Ubuntu 16.04, NVIDIA GTX 970, Proton 3.7-5 Beta:
Steam System Information
^ Easy Anti-Cheat regularly removes players during matchmaking session
^^ Default graphics preset is Best Quality
^^^ Default VSync setting in On