Poorness,
I know it’s frustrating to get done with a pedal and discover that one thing isn’t working right. Sorry for your frustration.
You said that the tap time is working, correct? If the tap footswitch is working correctly then the issue probably is on the analog side of things…meaning an issue with the voltage getting from the rate pot to the microcontroller. On the schematic you can see that the center lug of the rate pot (VR2) is going to pin 24 of the microcontroller. So test that with your continuity tester (with the pedal’s power off). Test it with the meter probe on pin 24 right as it exits the microcontroller’s body, not the solder joint because there could be an issue with socket. If that’s good then power the pedal on and measure the voltage on that pin as you rotate the rate knob. The DC voltage should scale from around 0 volts to around 5 volts as you rotate the knob. If you have trouble with these tests check the solder joints around pin 24 for shorts or opens. You can also test that the left and right rate pot pins are connected to ground and the 5V rail.
Do these tests and let me know what you find.
-Brach