The complexity of the synth waveform itself can play into how accurate the pitch detection is. You mentioned FM … I try to approach synth input with simpler waveforms. Add the complexity with the post-processing.
For example, multiple detuned copies of a ‘Hoover’ patch going into MicroPitch detuning can get a little crazy.
That said, I throw all sorts of pitch changes at the H9 – deep vibratos, extreme / unnatural pitch bends, etc. – and it performs admirably on pitch tracking. You can get it to glitch, if that’s what you’re after. Beyond the PitchFactor algorithms, CrushStation & PitchFuzz come to mind as consistent performers. Don’t forget to adjust your global Source parameter appropriately [Synth Lead; Synth Bass]. This H9 Algorithm Guide might help:
