All of our VFDs have shipped with a circuit similar to the one @gibs posted. You need something like that to do it correctly (I’ll assume his is correct; I didn’t look closely).
The Shapeoko 5 Pro electronics were designed to eliminate EMI/ESD as much as possible, which meant adding optoisolators everywhere, including the spindle output. That might mean that you need some signal conditioning to get your VFD working with it. Our VFDs already include that.
There are people who’ve opened up the electronics and connected directly to the CPU pin to get the raw PWM signal. Obviously, we don’t recommend that, but it’s your choice.
Support will work with you to make sure your electronics are not missing the pull up resistor, which would be a problem for you. I can’t tell from your shipping date if you might be affected, but I think yours probably shipped before the batch with problems. If you’d like to just swap out the electronics that you have, let Luke in his email thread from support.
I’m going to lock this thread because we’re in a loop here (and it was already scheduled to close tomorrow anyway). Your point is clear, our point is clear.