I was under the impression that 99.99% of fixes in the unofficial patches were gameplay related things, not underlying issues with the engine.
I also feel like if every game had the player count and mod support of Bethesda games, they would all have unofficial patches. No game is perfect and bug free, I know Bethesda games are buggier than most, but they are also way more ambitious and have way more content than most (I’m talking pre-starfield here, I haven’t gone back to starfield like I still go back to fallout and elder scrolls)