You can, technically, but there are some caveats.

SteamOS is not a general purpose OS. It is optimized to run on the Steam Deck (plus the Frame and Gabecube I guess). Its software components are tested on a limited range of hardware (specifically AMD silicon), and it might not have certain optimizations and compatibility fixes that are required by other consumer hardware. It also probably has some proprietary bits, especially the firmware.

The best option is Bazzite. It’s not based on SteamOS, but it is built with a robust gaming experience in focus. You can even get it to boot directly into Steam Big Picture. Watch this loud Aussie man do it!

The other option is HoloISO, which is an independent reimplementation of SteamOS. Their intention is to get as close to the real SteamOS as possible. Hardware support is limited (especially nvidia).