I’m curious about what algorithms you’ve tried (and didn’t care for), and also what OC-3 Mode you’re looking to emulate. DRIVE Mode reminds me of an MXR Blue Box, so the Octaver algorithm would be my 1st choice there. I don’t think you’re going to get the POLY Mode in a single algorithm; especially not the selectable range.
I’m liking the pitch shift improvements in the newer H9 Special algorithms. For cleaner octaving, I’ll often reach for those over the dedicated pitch shifters from the PitchFactor stompbox. Sculpt has a nice (one) octave down.
PitchFuzz can blend -1 octave, -2 octaves, plus a unison doubling. [Either one can be with / without added distortion]. Voice mixing takes a little thought. I tend to push those sub-octaves back a little in the preset mix when I don’t need the overpowering thunder. Believe it or not, that’s where I’d start for the OC-2 mode.