#ActivityPub specs are basis for spec compliance.

Current fediverse is a mixture of flavors. Mastodon is a flavor. The #FEP is a recipe cookbook for particularly flavored meals.

The fedi as it is today will never offer a home to anything that does not in some way represent a timeline with flowing texts, even if masquerading in more creative UI's. Every specialist (not really, just different-than-microblogging) domain auto-excludes itself to live in the fringes of fedi. Just by being different.