Bingo, yes this is the same issue for what they say. I am connected through DisplayPort though on all my screens. Shame that it is not being worked on but from my testing I assume that when steam moves proton to support wayland natively it will be fixed. Thanks for the info, very interesting!!

Thanks for the input! I tried it but no luck, the black blocks are still there and it still renders on 16:9. Thanks though!!

I think you are correct assuming it’s an issue with proton not supporting wayland as if i try to use lutris proton still doesn’t work but wine does and so does with gamescope.

I’m trying to use gamescope now as you and the other comment have mentioned but I’m having the issue with this command, if you could help me:

gamescope -w 3440 -h 1440 -W 3440 -H 1440 %command%

It creates a window of the appropriate size but the game is still in 16:9 (Without the black blocks issue, which is already a win, but i’d prefer it to be ultrawide too).

Thanks for the help!!

EDIT: Just tried it with Lutris but it seems to also not work even with their setup on proton. So it might be a them thing. For now I’ll just use lutris to play on wine directly.