This can be used in unity to convert the scale of the object to be the size of its collider. Note: it does also remove the mesh and resets the scale of the object

SetColliderSizeFromScale.cs

// Ethan Bruins 2019
// https://gist.github.com/Westerveld/fc81c4f51846c7153df8715fe5b76ddd

using UnityEngine;
using UnityEditor;

public class SetColliderSizeFromScale : EditorWindow
{
    //Shows up in the hierachy when placed in the GameObject menu
    [MenuItem("GameObject/Convert Scale To Collider", false, 0)]
    public static void ConvertObjectStatic()
    {
        //Get the selected item in the hierarchy
        GameObject[] objsToChange = Selection.gameObjects;
        Vector3 size;
        //Check it has a collider
        for (int i = 0; i < objsToChange.Length; i++)
        {
            //Check it doesnt have a local scale of (1,1,1) because there would be no point doing the change
            if (objsToChange[i].transform.localScale == Vector3.one)
                continue;

            size = objsToChange[i].transform.localScale;
            if (objsToChange[i].GetComponent<BoxCollider>())
            {
                //Get the collider
                BoxCollider col = objsToChange[i].GetComponent<BoxCollider>();

                //Set the size of the collider to our local scale
                col.size = size;
                //Revert the local scale to (1,1,1)
                objsToChange[i].transform.localScale = Vector3.one;

                //Remove MeshRenderer and MeshFilter
                DestroyMesh(objsToChange[i]);
            }
            else if(objsToChange[i].GetComponent<SphereCollider>())
            {
                //Get the collider
                SphereCollider col = objsToChange[i].GetComponent<SphereCollider>();

                //Set the radius of the sphere collider
                col.radius = GetBiggestValue(size) / 2;

                //Revert the local scale to (1,1,1)
                objsToChange[i].transform.localScale = Vector3.one;

                //Remove MeshRenderer and MeshFilter
                DestroyMesh(objsToChange[i]);
                
            }
            else if(objsToChange[i].GetComponent<CapsuleCollider>())
            {
                //Get the collider
                CapsuleCollider col = objsToChange[i].GetComponent<CapsuleCollider>();

                //Get the biggest axis of the vector
                col.direction = GetLargestAxis(size);
                //Get the value of the biggest axis, and multiply by two for height
                col.height = GetAxisValue(size, col.direction) * 2;
                //Get the second biggest value, and divide it in two for the radius
                col.radius = GetOtherValue(size, col.direction) / 2;

                //Revert the local scale to (1,1,1)
                objsToChange[i].transform.localScale = Vector3.one;

                //Remove MeshRenderer and Mesh Filter
                DestroyMesh(objsToChange[i]);
                
            }
            else
            {
                //Return an error if no collider
                Debug.LogError("No box collider on " + objsToChange[i].name);
            }
        }
    }

    //Returns the biggest value unless they are all the same then just returns z value. Usefull for the sphere
    static float GetBiggestValue(Vector3 vector)
    {
        if (vector.x > vector.y && vector.x > vector.z)
        {
            //X is biggest
            return vector.x;
        }
        else if (vector.y > vector.x && vector.y > vector.z)
        {
            //Y is biggest
            return vector.y;
        }
        else
        {
            //Z is biggest
            return vector.z;
        }
    }
    
    static int GetLargestAxis(Vector3 vector)
    {
        if (vector.x > vector.y && vector.x > vector.z)
        {
            //X is biggest
            return 0;
        }
        else if (vector.z > vector.x && vector.z > vector.y)
        {
            //Y is biggest
            return 2;
        }
        else
        {
            //Default to Y as thats the intial direction of the capsule collider
            return 1;
        }

    }

    static float GetAxisValue(Vector3 vector, int axis)
    {
        switch (axis)
        {
            case 0:
                return vector.x;
            case 1:
                return vector.y;
            case 2:
                return vector.z;
        }

        return 0;
    }

    static float GetOtherValue(Vector3 vector, int axis)
    {
        switch (axis)
        {
            case 0:
                if (vector.y > vector.z)
                    return vector.y;
                else
                    return vector.z;
            case 1:
                if (vector.x > vector.z)
                    return vector.x;
                else
                    return vector.z;
            case 2:
                if (vector.x > vector.y)
                    return vector.x;
                else
                    return vector.y;
        }
        return 0;
    }

    static void DestroyMesh(GameObject go)
    {
        //Ensure the components is on the object, then delete them
        if(go.GetComponent<MeshRenderer>())
            DestroyImmediate(go.GetComponent<MeshRenderer>());

        if(go.GetComponent<MeshFilter>())
            DestroyImmediate(go.GetComponent<MeshFilter>());
    }
}

Hi~
I see you have a method "GetAxisValue" (Line 119)
you can actually use vector[size] to do the same thing!
see: https://docs.unity3d.com/ScriptReference/Vector3.Index_operator.html

Just FYI, have a good day~