One problem with this that I've found through similar endeavors is: the act of making the library results in you knowing how it works on a deep level. It's likely you don't know React on such a level. This inflates your perception of how easy to use it is. If you did know React that well, you'd probably be able to use it very effectively!
Anyway I did take a look at Mutraction and it looks great actually. I've just made a lot of abstractions at work, and always been a little surprised by how hard it is for people to get used to them. Of course maybe I'm just bad at it. But ultimately it's made me kind of anti-abstraction all around. If everyone was as good with vanilla HTML, CSS, and JS (actually I'll approve TS) as they are with React, the web would be a better place </opinion>
Before I built this, I spent a couple of weeks reading the react source code. Of course, it's huge, and I didn't touch most lines. Probably never saw most of them. But it was enough to understand dispatchers, work scheduling, and fibers.
But you're right though. I still understand my own library better. However, I've really made an honest try to understand react (at least the client&DOM parts) as much as I practically could.
I think I'm on-board with your anti-abstraction POV too.
Anyway I did take a look at Mutraction and it looks great actually. I've just made a lot of abstractions at work, and always been a little surprised by how hard it is for people to get used to them. Of course maybe I'm just bad at it. But ultimately it's made me kind of anti-abstraction all around. If everyone was as good with vanilla HTML, CSS, and JS (actually I'll approve TS) as they are with React, the web would be a better place </opinion>