The value judgement implied in "invented concepts" is kind of weird, and maybe gets at a core difference in how you and I think about this.

Frameworks have APIs; they define concepts. Learning concepts isn't a bad thing in and of itself. Especially if they are concepts which let you model your application more succinctly and efficiently.

What you mean is that you are leaving it to the user to learn (or conceive of) additional concepts which are external to Gea to in order to build non-trivial reactive applications.

But "Gea requires you to write less code / know fewer concepts" can be reframed as "Gea opts out of solving some types of vanilla JS boilerplate for you". When you don't give your users "concepts", they're still going to end up writing a lot of code and learning concepts, just not within your API.