I stopped watching around season 18. There were still some funny moments, but they were becoming less and less. I absolutely hate Randy and the overabundance of his character on the show anymore.
I had some time around the holidays to watch the Post Covid specials, the first time watching in several years, but I found it pretty good overall. Cartman is still the best thing, the mileage they've gotten out of him all these years is astounding.
I've heard people say that the altered timeline where Cartman becomes miserable is deserving of his character, but I have to disagree. The Covid timeline showed that even a terrible person like Cartman can turn his life around, so in the end I did end up feeling bad for him since he gave the ultimate sacrifice.