I have an obejct which I can move up and down on the Y-axis and is limited to a min and max value. Let’s say you can move it from a random value like 0.173 up to 0.298.

I then would like to have a different value which changes dynamically from e.g. -30 to +30 depending on the objects position on its Y-axis. Ideally this value would change in ±0.5 steps.
Right now I can only think of manually “binding” the value on the y-axis to the other value like 0.173 = -30, 0.177 = -29.5, 0.181 = -29,…

You can get there with a bunch of functions. I’ll explain what each step does;

//These are the min/max for your object's y-axis (you would already have these)
float yMin = 0.2f;
float yMax = 0.4f;
//These are the min/max for the function output (the range to convert to)
float fMin = -30f;
float fMax = 30f;
//The size of each individual step
float step = 0.5f;
...
//y-axis position of the object
float y = transform.position.y;
//Re-map into a range of [0f,1f]. If you don't want the function to go outside the range, you can clamp this using Mathf.Clamp01()
float t = (y - yMin) / (yMax - yMin);
//Using t, re-map into the range of the function
float range = Mathf.Lerp (fMin, fMax, t);
//This is the final value. We scale by the step amount, round down to the nearest integer, then scale back into the original range. This allows you to step through a range at a specific interval
float f = Mathf.Floor (range / step) * step;