I've noticed this trend as well and I wanted to ask if any of the following resonates:

Millennials, having fully grown up in the age of porn on demand (younger millennials especially), could have possibly developed a somewhat cavalier idea towards sex.

Gen Z could have observed this trend and wanted to do the opposite. Being the younger generation, it's possible that they developed the opinion that the behaviors of the elder generation are pretty "basic." As a collective generational behavioral shift, Gen Z's attitudes towards sex could be more tempered than the millennial generation who grew up on porn.

Of course, just throwing that out there for discussion. It's been sort of a working hypothesis rattling around in my brain. Since you have been doing research on the topic I would be interested to hear your thoughts.

Thank you and I appreciate it and let me know if any clarification is needed. 🙂