yeah, of course it boils down to trust and "loyalty" of receivers not leaking

having public key of users you can do symmetric encryption of content and distribution of only such key for each viewer (be it pgp style or whatsapp groups or any other way to achieve "group encryption")

would be a way to take heat off relays (they cannot censor / cannot see content) and also basically have an hidden profile (only metadata leaked as in time/size/amount of recipients) accessible for example only to subscribers. 

or for example send them the symmetric key when a certain amount of sats thru zaps is sent... sort of like medium style "articles" with "pay per view" on each post, some posts or how you desire  

 Well, Nostr does have private messages.
The issue with private messages is that everyone can still se who is sending a private message to whom, at what time and how long.
The only private thing, which not even relays can see, is the content of the message.

My point was that Nostr isn't very dissimilar respective to your direct control of things that you publish (not just send to others privately): whatever you use, others may use that content in any way, including illegally. It's not really something you can technically prevent. 

 yeah,DMs but instead of 1to1 being 1toN

agree that it doesnt fix everything but would be exactly like onlyfans for example 

 Sure, you can do that with Nostr.