Definitely liking how ActivityPub works with my two blogs. However, there are a few limitations.
http://elizabethtai.com/2023/10/15/some-flaws-with-activitypub-and-wordpress-com-integration/
It might be explained by the way ActivityPub was designed with content coming from Actors, which explicitly don’t have to be individual humans.
So it’s sort of like your Mastodon presence is one Actor while your blog is a separate Actor.
This kind of thing makes sense when you remember that ActivityPub was designed to be centered around instances and not users. Actors are basically how instances are crediting the sources of what they’re publishing.