I personally saw lots of social media activity for ROP, mostly because the algorithms know I like LOTR. But yeah, definitely not as much as Stranger Things or Euphoria or HOTD.

You're right about younger audiences -- I'm Gen Z myself and I don't think any of my friends care about anything LOTR related. I don't think that's necessarily an indicator of viewership, because from what I've seen the overall viewership numbers for ROP are fine.

I think it says more about LOTR's target demographic -- it skews a lot older than those other shows. The movies are 20 years old, and the books are nearly 70 years old. And they aren't exactly light reading for kids. High fantasy in general is also a pretty niche genre compared to the fantasy in GOT/HOTD.