Protect a page from higher levels or all registered users?

I have my navigation in the wordpress backend and I want to hide the register link from everyone who has already registered. What is an easy way to do this? Will I have to make a separate menu?

How the site will recognise is the visitor (non-logged user) is registered or not?

The website already hides protected pages from non logged in visitors and members with lower levels of access. I just want this to do the opposite.

“Page Level Restriction” in the edit page page the only options it has are for level X or higher.

Just use CSS, using the class logged-in as well as the more specific attributes of this link, to hide the link.

I didn’t realize I had CSS classes hidden in screen options. Thanks