According to some data mining from the guy who runs SteamDB:
Steam is still working on clip recording. It supports background recording, includes timeline markers in supported games for various events.
Clips can be shared similar to screenshots, via the Steam community.
We don’t actually have any proof that this will be coming to Steam Deck yet, but I’m pretty optimistic that it would.
I recommend clicking through to the article, it has several screenshots showing how the feature will look.
Hopefully they can get game broadcasting working on Linux, too.
It’s so dumb how game streaming and remote play together, work, but if someone just wants to watch, no can do.
Fortunately OBS has native game capture plugins available on Linux now (not officially, you may have to install it from Github or the AUR). So you could use that to stream to YouTube or twitch for the time being.