On Bottles with the default runner I always had the mouse focus glitch. On Steam Proton Experimental it works great! If you play on BNet, I suggest you switch to Steam.
Yes they falsely banned Linux players two times in the span of 7 years and reverted both ban waves. It took them a few days to automatically unban me and the support wasn’t helpful, but that’s to be expected in a ban wave.
They’ve actively fixed bugs plagueing their games running on wine for decades iirc.
But some bugs like the mouse bug are really annoying.