If you look at the VCV free VCO in the scope module, the waveshapes it generates for the Triangle, Saw, and Square waves are not what I’d typically see in analog triangle-core VCOs. Is it trying to emulate a sine-core VCO? I really like these waveforms and am interested in emulating them in analog circuitry on a breadboard.
The open source code for VCV VCO as well as all the other VCV Free modules is available at https://github.com/VCVRack/Fundamental. Maybe it will answer some of your questions.
The ringing is due to band limiting to avoid aliasing. The “droop” is because it is high pass filtered to be “more analog”. Is that what you are asking about?