The preferred pattern addresses your concern about scattered logic: a single long-lived SSE endpoint that "owns" the user's view of the app. That endpoint updates their field of view as appropriate - very much inspired by game dev's immediate mode rendering.

I've a tutorial that demonstrates this with Nushell as the backend: https://datastar-todomvc.cross.stream

An interesting characteristic of Datastar: it's very opinionated about the shape of your backend but extremely unopinionated about how you implement that shape.