I highly recommend listening to You Must Remember This, Karina Longworth's movie history podcast. Specifically, the most recent two seasons have been about sex in movies in the 80s and 90s. She does a lot to ground changes in depictions of sex in movies in their political and cultural moment. The episodes vary in quality, but the best have been enlightening. I think she's sympathetic to the narrative that "Gen Z is prude" because she's a big fan of nuanced depictions of sex in movies, and sees a decline. And yet, listening to the podcast you can't help but see these trends as somewhat cyclical, which is why I'm not worried.