There’s no such thing as a “Linux PC” though. A PC is a PC. Your PC can run Starfield with proton, or it can run it by installing windows, or it can run it by putting it in a windows VM.
Even if a game can only run on Windows and Xbox (say one of those GAAS shits that has invasive anti cheat), that’s not an exclusive either. It runs on more than one platform. There’s a developer endorsed way to buy the product on more than one platform. Exclusive means one platform - you can’t buy and play the game unless you own one specific device.