How Do I Force DirectX 10 Without Using "-dx10"?

[SirArthurYeetcannon]

I'm running the latest Proton 4.11 on my Ubuntu install. I know my laptop can run KF2 (I ran it on Windows to test), but it needs DirectX to be at v10 because the Quadro FX3800M doesn't support DX11. When I ran the game with -dx10 on Windows, it was cruising along just fine at around 60fps on the lowest settings. I didn't want to keep Windows installed on my machine because the OS gets slow very easily, so thinking I'd figured out how to get this game running in Linux with Proton I switched back over to Ubuntu.

I know there's the launch option of -dx10, which worked when I ran this under Windows as I stated before, but for some reason Proton ignores launch options and tries to go into DX11 mode anyway. I tried messing with the Proton user config file as well, but disabling DX11 just made the game crash in a different way on startup; I think by disabling DX11 in the Proton settings it's trying to default back to DX9 which doesn't exist for this game. There is no Proton launch option to force anything to DX10, only 11 or 9 it seems. So with Proton's "backend" config files being no help, I need to rely on the game files themselves to force it to start and run in a DX10 mode.

Are there any other ways I can force this game into DX10 besides the -dx10 launch option? Any help would be appreciated. I KNOW my computer can run this game comfortably, it just needs to be on DX10 to do so.

Thanks in advance.

[-Dare Devil/x/]

-You can try the .exe itself. Can't you add launch parameters on it? I don't quite remember the specifics though.

[SirArthurYeetcannon]

Originally posted by -Dare Devil/x/:

-You can try the .exe itself. Can't you add launch parameters on it? I don't quite remember the specifics though.

I can't run the .exe directly because it will complain that I need to run it through steam. Probably an anti-piracy measure. Beyond that there's no way to inject launch options to the .exe directly in Linux anyway since .exe's aren't native binaries it can run. Unless I can somehow force Proton to use DX10, or mess with the game's files themselves to force it into DX10, I'm screwed. Which would be a shame since this computer can run it just fine, it just needs to be in DX10 to start