Currently there is a bug related to prefix generation on proton > 7. On the github issue tracker it seems it's more related to NVIDIA but - it also affect full AMD setups for some reason. Not getting much into details: You have to first launch this game with proton 7 to generate prefixes after that you can switch back to proton 8. If you already launched it with higher version you're little toasted so you will need to do few more steps. First kill the game/steam process (because it's probably hang) or better just reboot your machine. Next go to steamapps/compatdata and delete 2239150 directory. Go back to steam, set proton 7.0-6 and launch the game. If game lauches exit and switch back to proton 8 or experimental.