The Steam Deck is software-freedom friendly

They’re not saints, especially with the games distribution platform monopoly they’re sitting on top of, but...

I really think Valve have become the de-facto owners of the “don’t be evil” motto nowadays, even if they don’t advertise themselves as such.

Unlike other corporations, they actually didn't really do all that much to make it a monopoly though. It's kind of an organic monopoly simply by being better than everything else, by a wide margin.

There's not much "lock-in" apart from the games one owns on the platform; and the social aspects of steam are mostly negligible or niche - sure there's the friendlist, but no gamer I know uses steam voice-chat so the friendlist is mostly replicated in discord and similar anyway.

The library one amasses is a huge lock-in though, you’re downplaying it