In main this game works with proton (AND WITH LAUNCH SETTINGS, IT'S IMPORTANT, BECAUSE CAN BE LAGS) like native (in Windows). I don't know, what i can say more. I don't know why in Linux works better, must be conversely, and it's all without a bugs and other shit.

Just for compare, FPS in BL2 on Linux systems (180-200 on high graphics settings) high than in Windows (100-120 on high graphics settings), given my hardware. I played in Full HD resolution, it's 1920 on 1080.