I've used JUCE to create a C++ plugin that uses VST instruments and effects in TouchDesigner. You can control most VST parameters from CHOP input. You can even control them at audio rates. For example, at 60 FPS, one frame of 44100 Hz audio is 735 samples. You can select a "block size" smaller than 735, and parameters will be updated that often. So if you pick a block size of 64, in one 60 FPS frame, you'll have 12 updates (735/64 rounded up) of the parameters within that frame. Furthermore, with instruments, you also have subframe accuracy of turning notes on and off.
Check it out on Github: https://github.com/DBraun/TD-JUCE
* This project has no official affiliation with JUCE