As a user, you could argue that ATProto is "more decentralized" because you can (not right now tho) virtually move PDSes and change names easily. But that's obviously achieved by some relative centralization.
I feel people on both sides conflate *federation* and *decentralization* (sometimes accidentally, sometimes not?) and it creates a lot of the confusion/arguments going on.
I don't know if AP or AT is more decentralized. I know Dan Abramov had a metaphor that I find a bit silly but (at least to my scrutiny) holds up:
- AP/federation is having to choose where (neighborhood/country/what-have-you) you build your house
- AT is like having to choose an internet provider. (source: https://bsky.app/profile/danabra.mov/post/3la3ktrb3t22l)
The latter is sold as a positive, but that obviously means you're dependent on like... everyone else above "you" not being shady :P