If you don’t want to be called there to always it support it, go for off the shelf solution. Both qnap and Synology offer the same. When i looked half a year ago, i saw Synology as being more expensive at the time so went with ts464 qnap.
Qnap do provide a roadmap of support for older devices. So you have an idea how long they will remain supported for.
Can you actually use steamdeck as a desktop PC though? Can it drive dual external monitors? Is it a reasonable “minipc” type thing? How much power does it munch on in idle?
Can I maybe put some other linux distro on it? So many questions