The game has worked flawlessly for me in Linux using Steam Proton over the last several months, but I also had to use the workaround of using the old launcher. Throwing my +1 on the pile for no longer being able to login due to this forced update. Really frustrating that the launcher of all things is what's preventing us from playing.

if anyone happens to find another workaround by any means (such as winetools), please share it!