To me something git-like with a peer review UI (a la pull requests) seems far more natural for distributed academic publications than a social media protocol though.
ActivityPub, based on my understanding, really doesn't work like that - while you an oauth with your mastodon account, the expectation is you'll be handling identity and back-end bits, and then sharing events across the network (happy to be corrected).
Part of what kicked this off is seeing ATProto's new devrel person at a meetup and finding their vision pretty compelling.
But yes, ActivityPub is more "robust" and decentralised (hence also jankier)