Ended up just making a separate steam account. Though on my steamdeck it 'helpfully' shows recent updates for all games for all accounts on the device even if they aren't logged in, which is annoying.
Just be aware that on multiple occasions having my profile set to private has broken multiplayer, specifically friends being able to find and join me in several games. I think it's really dumb how privacy settings seemingly have in-game effects, but it is what it is.
Ended up just making a separate steam account. Though on my steamdeck it 'helpfully' shows recent updates for all games for all accounts on the device even if they aren't logged in, which is annoying.