Not sure if this has been posted here yet, but I don't feel like digging atm to check so at the risk of echoing; this fix is basically a must do if you care about how the quality of your game looks and don't use the hq mod.
The recent updates took maximum texture quality of world objects down from 2048 to 1024 automatically, even if you play on completely ultra.
Littledica basically saved my life today and posted the way to fix it here:
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I hadn't noticed it in game (probably because I was barely going in game and stayed in cas 24/7) but i do use create a sim background replacements, sometimes my own, and sometimes littledica's 3d create a sim background override. Due to them being world objects just used as an override, they literally went from crisp and clear one day, to gta san andreas the next day and I thought I was crazy. Changed things around in nvidia control panel, checked the overrides in sims4studio to see if anything was wrong with them, but nothing. It wasn't even a tolerable quality drop. It was horrific. Got to the point where i had to start using solid color cas backgrounds which I like, but they do feel very empty in comparison to cas background overrides that mimic rooms.
But yeah, if you've noticed that your cas background overrides or just world objects in general look blurrier than they did before- that's because they are. Please do the fix, lol. I missed using my cas backgrounds so bad for like 2-3 months.