Hmm, maybe if an app’s creator hosted their own instance just for accounts (i.e. with no posts of its own). That way, a new user can download an app, set up an account on that app’s dedicated accounts server, and start browsing all the other instances from there.

I agree. The information should be easily available if they are interested, but end users shouldn’t be required to know about the underlying mechanics of the fediverse simply in order to create an account and browse.