SteamOS has the root filesystem set to read only, this is because of the way the system gets updated, and also makes it sure that every deck is running the same system. So you can’t change system configs or install things on the system. You can get around these by installing things for your user and creating services for your user. It’s doable if you want a gaming device that you use for some other things, but it’s not very convenient for a day-to-day drive.