Steam Deck Linux Help

Anytime I replace the cod4mp.exe I can get on 1.7 and see the Cod4x list. But I can’t join any servers I get an error that says Awaiting Challenge… then eventually get “Can not connect to the server because the update backend is unavailable.” And that I have to update manually. Only thing is I can’t run install.cmd on linux as far as I know. Though, I used to be able to run cod4x on my steam deck before? It was as easy as joining a server and installing it, but that isn’t working now.