Can't comment on the bluesky aspect, but you've touched on my frustration with ActivityPub. When people were migrating to Mastodon, I took a look at making a single-user instance that would suit my personal needs and gracefully interact with the wider ecosystem and found that in my case the capabilities of ActivityPub are irrelevant, you are tied to the Mastodon teams choices.
Felt very much like in practice it just gives you tools to make mostly-insular federated apps, rather than letting different apps interact.
Felt very much like in practice it just gives you tools to make mostly-insular federated apps, rather than letting different apps interact.