This is an issue with Mastodon (and most of other software that implements only the push-based processing of inbox), but there is nothing on ActivityPub that prevents a client to directly read the actor's outbox.
As a matter of fact, I am working on a fork of a elk right now that is meant to function as a pull-based reader of AP data, so pretty soon you will be able to have your SSG generate an outbox for you and I would get all updates, boost it, etc
As a matter of fact, I am working on a fork of a elk right now that is meant to function as a pull-based reader of AP data, so pretty soon you will be able to have your SSG generate an outbox for you and I would get all updates, boost it, etc