(no, seriously, its really simple.)

This can be done trough Flatpak (Steam Deck)
Or
Using your package manager (Every Linux)
In my case i use Arch Linux (Garuda) so i can use "yay protontricks" or "sudo pacman -S protontricks".
Search for your distro on how to install it!

• protontricks 658150 d3dcompiler_43 d3dx9_43

This is gonna install some necessary dependencies for the game to work! Idk if this work too in Steam Deck (Using terminal) Search for the way you need to do it. (I think its more manually, opening Protontricks and searching the game.)
I dont have a Steam Deck now to say how to really do it, but this is for helping someone that is really desperate in how to play it.

If you need help in something, write it in the comments, and fell free to give me awards or that type of stuff, i'm thankful for it ^^.
And also, i hope some developer sees this and use it as some sort of help, and remember, Use ProtonDB!