I completely understand where you’re coming from. I wish that Glide allowed us to use the RowID of the Users Table as an alternative to the email address when enabling row owners. Perhaps I should make a formal feature request if it doesn’t already exist.
To make a truly private chat, you’ll need to use row owners. The only way to enable row owners (in this use case) is by leveraging email address. The only way you could allow email address and maintain user privacy is by enabling “anonymous emails” in the app settings.
Perhaps someone else can chime in here.