Is the cable for the stepper shielded? Do you have an end stop on it? I use an inductive end stop on mine. Printed a bracket to home it and another bracket that attaches to the chuck back side. I put a 3mm bolt in the chuck side to trigger the sensor.
That way I have an accurate starting point each time. If indexing only, you could home on each rotation to get back to zero repeatably. I haven't had to use it like that myself. I just thought I would have to if forces were high enough to change position during a cut.

I know it's not a great option considering you definitely purchased it for the ability to set an angle correctly.

Sent from my SM-G996U using Tapatalk