Steam

My partner and I are sharing our libraries with each other on both the Steam Deck and our desktop PCs, but the list of actually borrowed games constitutes only a fraction of our complete libraries. I would expect all (non-F2P) games to show up under either borrowed or excluded.

From searching around, it seems to be a recurring problem for various people, and it either spontaneously fixes itself or after deauthorising and reauthorising (some reporting they had to clear Steam's cache - which is the only thing I haven't tried yet because that would be a massive inconvenience). But I'm not finding a lot of solutions or answers to what the deal is.

Has anyone else dealt with this?

Edit: it looks as if the listed "borrowed" games are only those that have been actually played at some point, so it's possible the list isn't meant to be exhaustive. Doesn't explain the missing majority of games however.

Edit 2: I don't know if it was always the problem, but I just realised I had "show only ready to play games" selected, which obviously excludes all uninstalled games. I noticed because I tried downloading a game through the other account to see if that changed anything, and indeed it showed up. Mystery solved, hopefully.

(In a petty attempt at salvaging some dignity I want to add that I've had the problem of shared games not showing up before and I could swear this was not the problem...)