How to find or compute or look for overall/max RPM by simply checking for rotation?

I find it hard to determine the wheel RPM since I’m only making a simple 2D game of rotating object via Z-axis. I wanna try this solution but I got no change since I’m trying to find the RPM from a game object that has a rigid body 2D and a circle collider. I decided to think of something more simple but alternate solution. I ain’t good at math and that took me around 4 days to guess but no luck. I want to know possibilities of checking its rotation from transform properties, figuring out yet about 6 degrees per second equivalent to 1 RPM as said from the link. I used the method transform.Rotate() for rotation speed. Please help me.

The info in the link does not looks rigth, if you game runs does not runs at 60 fps.

RMP means rotations per minute

1 rotation have 360 degrees

1 minute have 60 seconds

So

RMP * 360 degrees = degrees per minute

angles per minute / 60 seconds = degrees per second

After finding the degrees per second (angular velocity) do the steps in reverse to get the RMP

void Update(){
        currentEuler = transform.rotation.eulerAngles.z; // only care about the Z axis
        // if you remember you physics class displacement over time variation is equal to velocity
        yDegreesPerSecond = Mathf.Abs(currentEuler - previousEuler) / Time.deltaTime;
        ...
        previousEuler = currentEuler;
}