itch.io

Have you tried running it with Proton? It seems to work flawlessly with Proton-GE (installed through the AUR, but I'd imagine other packages work just as well). 

If you're using the itch.io app, you can trick it into using Proton instead of wine when it runs programs.

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First start by creating an executable named "wine" in a local folder (e.g. ~/.local/bin/), and edit its contents to execute a basic script to run Proton-GE:

#!/bin/sh
proton-ge "$@"

Then create another executable (let's call it "itch_script") and have it launch itch, this time adding your new "wine" executable directory to the start of your Path:

#!/bin/sh 
PATH="$HOME/.local/bin:$PATH" itch

**Make sure both of these newly created files are given executable permissions**

Finally, create a new itch.desktop file (placed in a location such as ~/.local/share/applications). You can copy the .desktop file that's naturally created when installing the itch client, but change the exec line to look at itch_script:

Exec="$HOME/.local/bin/itch_script"

You might also want to change the Name field from "itch" to something like "itch (Proton-GE)" to distinguish it from the other itch.desktop file (should you choose to keep it).

That's it! Then just launch the new .desktop file, and wherever itch would normally use wine, it should now use Proton-GE.

Note: I didn't come up with this idea, but rather found people discussing something similar and applying those same principles. I am also rather an amateur when it comes to bash scripting, so there is likely going to be a cleaner way of doing it. Ultimately this just works without issue for me, and I don't want to get bogged down in finding a better way.