This feels unfinished.

How is it that the “Add Link” toolbar button in notes shows this weird popover that only allows me to add a link to the frontmost website open in Safari (and Messages?!), but it doesn’t give me access to the new publicized feature of linking to other notes? I have to use the Edit > Add Link menu item for that.

Also, links between notes are useless without Back and Forward buttons.
You click a link and then what? Good luck manually finding the note where you came from?