How to shortcut a lambda expression through a function?

Hi, is there anyway to skip writing the lambda expression using a function. I'm trying to do a test where I can modify a referenced float through coroutine, using the System.Action with the lambda expression. I have two functions, an IEnumerator function, and a normal function to call the start coroutine with that IEnumerator function, and a float parameter in the second function, for a referencing a float in script or out, in-between the lambda expression.

Here's the example below.

 IEnumerator FloatTestIE(System.Action<float> refFloat, float startFloat, float endFloat)
 {
     float fTimer = startFloat;
     refFloat(startFloat);
 
     while (fTimer < endFloat)
     {
         fTimer += 1 * Time.deltaTime;
         refFloat(fTimer);
 
         yield return null;
     }
 
     refFloat(endFloat);
 }
 
 void FloatTest(float refFloat, float startFloat, float endFloat)
 {
     StartCoroutine(FloatTestIE((float f) => refFloat = f, startFloat, endFloat));
 }

But for some reason it doesn't seem to work.

It works fine when I put it in lambda expression on the second function like this.

 public float f;

 void Update()
 {
     if (Input.GetKeyDown(KeyCode.Z))
     {
         FloatTest((float x) => f = x, 1, 10);
     }
 }

 IEnumerator FloatTestIE(System.Action<float> refFloat, float startFloat, float endFloat)
 {
     float fTimer = startFloat;
     refFloat(startFloat);

     while (fTimer < endFloat)
     {
         fTimer += 1 * Time.deltaTime;
         refFloat(fTimer);

         yield return null;
     }

     refFloat(endFloat);
 }
 
 void FloatTest(System.Action<float> refFloat, float startFloat, float endFloat)
 {
     StartCoroutine(FloatTestIE(refFloat, startFloat, endFloat));
 }

But I want it like this to keep it clean for me.

 public float f;

 void Update()
 {
     if (Input.GetKeyDown(KeyCode.Z))
     {
         FloatTest(f, 1, 10);
     }
 }

 IEnumerator FloatTestIE(System.Action<float> refFloat, float startFloat, float endFloat)
 {
     float fTimer = startFloat;
     refFloat(startFloat);

     while (fTimer < endFloat)
     {
         fTimer += 1 * Time.deltaTime;
         refFloat(fTimer);

         yield return null;
     }

     refFloat(endFloat);
 }
 
 void FloatTest(float refFloat, float startFloat, float endFloat)
 {
     StartCoroutine(FloatTestIE((float f) => refFloat = f, startFloat, endFloat));
 }

If there's any possible workarounds or if it's not possible at all, I'm not very familiar the lambda expression or the System.Action thing, since I just discovered it recently, let me know anyway what you all think, thank you.