If you're interested in one, I would highly recommend getting a couple of months of game pass to try. Pretty much all of their first party games from the 360 and beyond are on the service, including a lot of third party stuff.
As far as what are interesting, what's your favorite kind of games? Casual racing? Try Forza Horizon 5, Sim racing? Try the new Motorsport, Shooter? The Gears games are pretty good. RPGs? Lots of them on the service to name.
Oh no it's not like that. Refurbs run the gamut from cleanish-used quality to units completely rebuilt with new parts. On average though, you are going to get something closer to the new side. Plus, they are qc'd on an individual basis so that can be better than brand new, which can be done in batches.
Give it a shot sometime you might be surprised. You generally won't get the retail packaging, so be warned of that. If I was getting a steam deck I'd go straight for the refurbs because I think valve would do at least a decent job of it.