[tumult]

I don't think Max4Live is not a good choice for building audio plugins. It's a weird platform that was designed for 'institutionalized academic music,' as I once read someone describe it. It's difficult to program in and not efficient. None of my favorite music software is made with it. It's also quite buggy, in my experience. For doing some basic extensions to Ableton Live specifically, beyond what VST allows access to, it's OK, since it's the only official way to do so.

If you want to just dive into DSP using wires and boxes, with some additional code sprinkled in, SynthEdit or Reaktor Core are faster, more fun, and produce better results. If you don't mind C++, check out iPlug from REAPER's WDL codebase: https://www.cockos.com/wdl/ — there are some forks of it.

There's also JUCE. You'll find some people complain about it and some people regret using it, despite it being relatively popular.

There are some Rust things for doing VST (and AU) development. Here's one that I've seen a few things made with: https://github.com/robbert-vdh/nih-plug/tree/master I wouldn't worry too much about the differences between C++ and Rust in this world. Audio software tends to be buggy, so the bar for being considered 'good enough' is pretty low.

[tumult]

Can’t edit this comment now, but the opening sentence has a typo. It should say, “I don’t think Max4Live is a good choice for building audio plugins.”

[laratied]

I have hated Max/MSP for at least the last 15 years. Designed for 'institutionalized academic music' made me chuckle.

Autechre's Confield album is what it is good at doing. There is nothing more to do with the software after that album.