The scale of the change is also a bit scary to me, but we can also see it as a chance to make the type system radically more powerful. The PEP process is slow, and this lets us batch a lot of improvements at once.
To move this forward, you should make sure the PEP gets implemented in typing-extensions and at least one type checker so people can play with it and we can get a sense for the edge cases.
The PEP currently targets Python 3.15, which has a feature freeze in about two months. I think that’s unlikely to happen; there’s simply too much here to digest and implement in two months.