It’s running Windows, and if you put it in dev mode, which is not much harder than putting a laptop off S mode, you can install anything. It works with a mouse and keyboard. Pretty close to a PC.
You can't install anything, only UWP apps that run in an extremely restrictive sandbox. You can get root on Steam Deck by switching to Desktop mode, opening the terminal and inputting a couple commands and you have full access to the hardware's bootloader.
