You ARE seeing less in recent movies and television shows, OP; it's not in your imagination that there's less nudity and less sex.
The younger generation (13-24 in this study) wants to see LESS sex in TV and film. Interesting study here:
https://www.npr.org/2023/10/25/1208435267/sex-teens-tv-movies
This got covered fairly broadly, not just by NPR, so if you don't like NPR, this study (done by UCLA) was covered elsewhere too. (I know, nudity is not equivalent to sex, but the study talked about sex.)
If young adults up to 24 (in the study) want to see less sex, I'd wager that the same is probably true among older 20-somethings. I agree, OP, that the 80s-90s TV shows -- network and especially cable--had lots more skin showing than we'd see now in many shows, except certain streaming shows
designed to be extremely sexual. And some recent streaming series that were promoted on the fact they were sexually explicit ended up flopping big-time. For instance, "The Idol" and "Obsession" were both promoted hard as series with plently of explicit sex and both got trashed by critics, in part for what sounded like the overuse of explicit sex and what many felt to be disturbingly violent sex. Basing plots around sex and showing it explicitly doesn't seem to be sitting well with viewers or critics, I think.
It's worth noting that what teens and young adults wanted to see instead of sex and nudity is