We need federated identity or else ux will continue to lag
What I am saying is that the ActivityPub protocol is inherently built towards a server-centric system, where identities are owned by the server. Go read the spec: even the "Client-to-Server" specification assumes that the server owns the keys and dictates that the client (i.e, users) must do everything through the API provided by the server (i.e, the client's outbox).
Anything that is built with a design where the client owns the keys may even be able to interoperate with ActivityPub, but is not ActivityPub.
Activity Pods is cool bit not implemented on mastodon.
It's the other way around. We shouldn't be looking for "Mastodon on ActivityPods", but "ActivityPods applications that can talk with Mastodon servers", and those do exist.
Sub.rehab is super outdated and https://fediverser.network/ is easier and crowdsourced.