Changing OpenCR PWM Frequency

Hello all, I have a problem with a university robotics project. As an outline: I am trying to control a BLDC motor controller via PWM. First problem: The motor controller provided does not speak PWM, only 0-10V for speed control. So I tried using a (cheap) PWM voltage converter but noticed afterwards that this converter needs a PWM frequency from 1-3 kHz, but the opencr board PWM runs at 50 kHz.

Ordering a different controller is not feasible because of time constraints, so I now face the problem of somehow changing the frequency of the output PWM.

I found a Github issue related to my problem, but trying to follow the steps taken by the author did not really lead me far… I am still a beginner at bare metal MC programming, so I am somewhat at a loss.
I programmed a PWM signal once using CubeIDE on a Nucleo Stm32 476 board, but I am unsure how this translates to an Arduino.

Do any of you have some pointers, code snippets, or alternative solutions to solve this?

I really appreciate any help you can provide.
Regards, Daniel

Got it to work, more or less. What confused me was the voltage level of the PWM pin - this seems to be at 3.3v, measured via an oscilloscope. I was expecting 5v, so my calculations were off.