Got good news and bad news nostr:npub1nd86x5za0ascfmvmsxqyrzk4xc7l48h6gfmlcf5d3e9munenydys4g2zkd.
Bad news first...
... your naming idea has been claimed by nostr:npub1f9fd738mny4rh95466l75u3raq4t65hcg2zm0qdcc0qgqn7g20lqn0dgxv for his new fediverse messenger app:
https://wedistribute.org/2023/08/sup-by-pixelfed-is-coming/
Good news...
... a lot of what you seem to be proposing is possible right now, by building new apps on top of the existing back-ends of any of the existing ones. This list may be incomplete but its being actively updated and you can browse by language and app types (micro-posting, blog, media-sharing etc);