Does high voltage cause- Stepper motor jitters / uncontrolled stepper?

Hello yall! Thanks in advance!
(Wiring Diagram attached)

So I am using:
Arduino Mega
ZS-H3 motor controller Link
quimat nema 17 stepper motor
4s power supply currently at 16v

When hooked up in the configuration in wiring diagram and I run one step at a time it maybe does two steps then jitters and reverses and spins kinda freely/uncontrolled.

When I put it on a 2s system at 7.9v, it seems to work better seems to step correctly?

Is voltage the problem?
Should I use a voltage divider or a buck converter if voltage is the issue?

You can't use a dual H-bridge motor driver for a low impedance stepper like that one, you are just going to fry the driver board horribly. The motor is meant to be current driven.

You need a chopper driver like the DRV8825, which does constant current drive.