I also have an Apple Watch to track heart rate/calories. There is no way to calibrate resistance compared to a Peloton bike, but the resistance knob can be turned almost 8 full revolutions, so I’ve just been assuming each full turn is 10-12 in resistance and I go by that (on my bike, when the negative sign on the knob is at 12 o’clock I …

https://www.amazon.com/Sunny-Health-Fitness-Magnetic-Capacity/dp/B07FCJH59R