> What I find time and again is that as I go far enough into some new interest, it starts to converge and connect to my other ones. I see similarities, or ideas where I can combine multiple interests to produce something that I couldn't make with just one of them.

I've experienced the same thing. I used to joke that if you go far enough in any discipline, you'll end up in philosophy and abstract math. But it's more than that. Reality does not recognize specializations and boundaries. Reality is that "amorphous blob of all of this stuff, jumbled together". Drawing boundaries help us make sense of the world, but it's important to recognize boundaries are somewhat arbitrary and we're free to redraw them to fit our needs better.