Earlier quoted context omitted.
That's still too heavyweight. You have just described something that is more complex than what a static site generator can produce. My static site doesn't have an "endpoint" for people to post notifications to. A like is nothing more than a way of saying, "I like this". Think. You can come up with a way to do this that doesn't require you to abandon RSS (read: Atom). If Alice posts something and Bob likes it, then he…
You are basically describing Nostr: https://www.youtube.com/watch?v=ssNkOMx2E5Y
I'm describing RSS (read: Atom) with better UX. Nostr is a from-whole-cloth new protocol that's fundamentally incompatible with everything I've laid out.
(The video you linked to is unwatchably obnoxious, by the way.)