@trwnh I didn't say that actors always map to "users", though mapping actors to "accounts" is very common and is a good UI design practice. In my proposal Application actor is recommended, which is not a "user".
The idea of adding inboxes to collections, or that collections could be followed is not supported by the ActivityPub specification. I believe it is also wrong for other reasons, and I already said enough about that in FEP-2277 and in various discussions.