Change prefab Material

Hey,

I have some Blender models with the same materials. The models stored as prefab in Resources.
In Unity I have a custom editor script to call this method that works.
I can load all Prefabs and their materials, but the Prefabs do not apply the new materials.

Here is my Code:

public class AutoMaterialSetter : MonoBehaviour
{
    public string prefabsPath;
    public string directoryResourcesPath;

 public void setMaterialToPrefabList()
 {
     GameObject[] prefabs = Resources.LoadAll<GameObject>(prefabsPath);
             
     for (int prefIndex = 0; prefIndex < prefabs.Length; prefIndex++)
     {
         //the new materials
         Material[] resourcesMaterials = Resources.LoadAll<Material>(directoryResourcesPath);
         //the old materials
         Material[] materials = prefabs[prefIndex].transform.GetChild(0).GetComponent<MeshRenderer>().sharedMaterials;

         //swap materials
         for (int materialIndex = 0; materialIndex < materials.Length; materialIndex++)
         {
             foreach (Material resMaterial in resourcesMaterials)
             {
                 if (materials[materialIndex].name.Equals(resMaterial.name))
                 {
                     Debug.Log("-------------------------------------------------" +
                                 "\nPrefab name; " + prefabs[prefIndex].name +
                                 "\nPrefab material name; " + materials[materialIndex].name +
                                 "\nResources material name; " + resMaterial.name);

                     /*Material newMat = new Material(resMaterial);
                     newMat.name = materials[materialIndex].name;*/
                     materials[materialIndex] = resMaterial;
                 }
             }
         }

         //apply materials to prefab
         prefabs[prefIndex].transform.GetChild(0).GetComponent<MeshRenderer>().materials = materials;
     }
 }

}