What if... you had one Fedi account on a generic headless #ActivityPub server that simply hosts and federates your data... and had C2S UIs for microblogging, long form writing, media editing and sharing, link aggregation, games, fitness tracking, and so on, that all used that same Fedi account. Technically, it's a similar concept as ATProto (but no relay and app view) and Solid Pods (but no RDF).
It seems possible... if we can improve the AP C2S API/protocol sufficiently.