Apple Vision Pro

Would you buy a light weight headset that’s only for watching movies?

if it's really, really immersive, without superfluous pricetag, and I can install my own OS, then I'm definitely interested.

Yes, especially if it had opt-in syncing nearby devices so I could enjoy movies with people I’m with. 

I love watching movies in AVP but it’s not a social experience at all, especially if those I’m with don’t have one

no amount of money could be paid to have me expose my eyeballs to that high level of up close blue light radiation

I prefer not to strap something to my head

Yes, as long as the video and sound quality were there. I like the idea of the movie screen adapting to you vs. the experience being based around the screen itself.

Absolutely! A lightweight headset just for movies