I agree. RSC is extremely powerful and impactful, compared to everything that has been going on for React since hooks. It is easy to understand as a concept, and it allows for proper composition of features on the server side. In fact it's remedying a lot of unnecessary complexity that React brought originally. RSC is what allowed me to accept doing SSG at all.
Server actions seems like a neat idea. Probably does nothing for large projects, but at least IMO it can be very useful for the smaller use cases.
It's a paradigm shift compared to the old way of thinking about React apps
In my company we've been using Next.js in production for a long time now and for us the app router has been key to increasing DX