Hello,
I am vice-champion in an International robotics competition called Eurobot, I have a very large experience with robotics and microcontroller programming. I can deliver a code which is well commented and well explained.
For the hardware I suggest using a servo-motor instead of the stepper motor, you will not have to worry about the control. Also, I suggest using an ESP32 instead of an Arduino (Raspberry Pi is too powerful for such application, using it wouldn't be an optimized solution), The ESP32 costs 5$ and it's programmed using the Arduino IDE, it has builtin Wifi and Bluetooth so we could turn on/off the knob wirelessly. I can suggest an App that will let you program any sequence you want.
Please contact me to discuss this further.
Thank you.