Max is a visual programming language[1] (arguably the most popular/relevant one?). There are some good screenshots of what it looks like here
https://cycling74.com/products/max/ It requires using the Max app, an IDE-like environment, to use. The `.maxpat` files are JSON but not meant to be edited by hand (although I do it all the time).
Reaktor is also a visual programming language. Both cost money, a lot actually, I think Max and Max for Live (which you need to run plugins in Ableton and is sold separately) are $600 or so total.
Visual programming languages are especially popular for synthesis, I'm assuming there's a reason for that, but honestly I've never tried doing this stuff in another language (most "native" VST-style plugins are written in C++), so I can't really compare it to that or give a real explanation for if it's better. But it is simply an environment that brings me joy to work in (despite its warts), so beyond doing a bit of work in Reaktor, I've never even looked into other ways of doing these things.
[1]: https://en.wikipedia.org/wiki/Visual_programming_language