Again, this seems simpler just to type the question that combing through 1000s of articles. Say someone wants to be your friend, how can you see what their server is offering before deciding? Or simply put, can you just be friends and NOT share anything?
You cannot see what is on their server without being their friend, but you CAN be friends without sharing anything. You would just accept their request and uncheck any server libraries on your end. You can also unshare yourself from their server libraries if you dont want them to show up.
Plex is for sharing your media with family and personal friends.
You won’t get any assistance for sharing with strangers and the whole internet at large.