The separation between PDS and appview is a great advantage. I guess ActivityPods's is trying to do something similar by unify Solis and AP, but I don't see much talk about it.
ATProto also has something alike Zot's "nomadic identity". And while there has been work to get it working on ActivityPub, only a few software support it and many don't even care about implementing it.
A big problem of the AP side of fedi is that while seeing itself as the most decentralised in quantitative terms, in some qualitative aspect acts in a semi-centralised manner either by making migration harder and incomplete or by being suspicious of any tool that separates identity from log in credential (nomadic identity, multiple identities, etc). It's pretty obvious that many AP devs and sysadmins have a user lock-in mentally and only defend the self-hosting aspect of decentralisation.