It's definitely NOT modular...but from my experiences in both hardware and the present-day software versions, the Synclavier is the sine qua non for this sort of harmonic series tinkerage. And nowadays, it's no more expensive than a typical multi-VCO module: https://www.arturia.com/synclavier-v/overview
And if you MUST make it part of a modular setup, then you can either cobble up a way for Silent Way/Volta or Ableton CV Tools to talk to it...or you can use VCV Rack and the included Host modules. Definitely loads easier to integrate as software than it EVER was in hardware, from my experiences.