Thanks for your Feedback. Yes you are right, most of the stuff happens under the hood, but more features that touch the admin UI will come soon.
Indeed, we had long discussions about RSVP in the Fediverse and I am working on unifying the behaviour of it.
The problem here is: the event plugin itself should offer a way to handle RSVP already. And it should do so in a way flexible enough to include it. But including it here in a generic way is almost impossible, or would end up being very clunky, having lots of confusing edge-cases. The RSVP solutions present in the supported event plugins are just too different.
That’s where the idea came up of developing an Event-Plugin with built-in ActivityPub support. Note that I am in contact with the developers of GatherPress, a community first event plugin.
On the other hand what would be easier is doing an independent RSVP –ignoring what an event plugin might already provide.