I have the same problem on my ps5.
It happened that my library was full, so I wanted to make sure that all the lots and sims are at least somewhere saved. But when I check my favourites, only one(!) lot is showing up. Changed the search criteria, but it stays just that one lot and no sim is showing up at all, no current or previous liked. Also when I search for them in the public gallery, they are marked as liked. That's so disappointing.
Update: I've put some creations to my favourites with the online gallery on my laptop. Some time later, I've checked them on my console. The lots and rooms are showing up, BUT still no household, no sim, no pet, no matter if I change the filters.
