There seems to be a serious lack of a Discord equivalent fediverse platform unlike other social media alternatives. Most of the closest options are either too overwhelming in UI/UX for majority of people coming from Discord, missing deal-breaking features like video calling or are not federated.

Could it due to some technical limitation of the ActivityPub protocol? I skimmed through its documentation and I get the impression that content may not be accommodating of instant messaging without unconventional modifications. It would also be troublesome to federate massive bunch of messages across (physical) servers in real time.

If it were truly possible to create a Discord alternative, what would it take to make it compatible with the fediverse while also ensuring it feels functional and intuitive for migrating users and not pose too much of a resource drain for self hosters?

Edit: Modified title to clarify post talking about ActivityPub in particular