The game can't/doesn't want to write cache

@bi0hzrd  I would find it fascinating if using DSR was what fixed the icons, so please test that and DEP separately and let me know what you find.  (DEP shouldn't be necessary anyway, but now I'm curious.)

For the world loading times, it's pretty clear that the WorldCache folder is the issue, but not why the game isn't reading it.  I'd suggest testing without DXVK just to make sure this isn't a side effect of that utility—it's very new, at least in terms of wider use, and any problems with it aren't well-documented yet.  Deleting the files and repairing the game is enough to revert the changes, although that would revert your .sgr files as well as anything else in the program files, so make backups if you don't want to redo any edits you've applied.

If you've made other edits too, please skip them for at least one round of testing.  That applies to any .sgr edits not directly related to getting your GPU recognized as well.  I realize that it's kind of a hassle to set everything up just the way you like it, but this is such an odd error, with no known cause I can find that we haven't already covered, it's time to eliminate as many variables as possible.

I'd also suggest trying to play with your computer completely offline.  And just for fun, see how much this mod decreases a new save's initial loading time (Sims Asylum, so you'd need to sign in to download it):

https://simsasylum.com/tfm/index.php?/topic/497-no-auto-placement-of-community-lots-in-ea-worlds-requires-at-least-one-of-these-eps-ambitions-showtime-supernatural-or-seasons

Some of that first loading time is directly related to placing these lots, although not all of it.  So I'd like to know how much of the problem is this and how much is the WorldCache data not being read.