I originally thought this was a bug, but it’s apparently a design decision. That Ghost doesn’t let you have private newsletters, even for internal testing purposes, is bizarre. Not every newsletter should always appear on the signup portal. Newsletter visibility at signup should always be a decision by the owner, not a default. Beehiiv and others do this, and not having it is a big problem.
I see others have complained about this for ages and been roundly ignored by people at Ghost. I like Ghost a lot, but some of the design decisions and, well … ghosting of support are just bizarre.