How do I get the color of a certain mesh vertex?

I have a custom mesh and I want to get the color of a separate triangle. I tried to use these solutions : https://stackoverflow.com/questions/45854076/set-color-for-each-vertex-in-a-triangle , https://stackoverflow.com/questions/57405631/unity-how-to-use-mesh-triangleindex-to-recolor-a-triangle-when-clicked?rq=1 . I don't have a texture on the object, so there remains only a way with manipulations of triangles and vertices. I was trying to get the color this way :

     // Update is called once per frame
    void Update()
    {
       Ray ray = camera.ScreenPointToRay(Input.mousePosition);
        RaycastHit[] hitInfos = Physics.RaycastAll(ray);
      //  Debug.Log(hitInfos[0].collider.GetComponent<MeshFilter> 
    ().mesh.triangles[hitInfos[0].triangleIndex]);
        Debug.Log(hitInfos[0].collider.GetComponent<MeshFilter>().mesh.colors.Length);
    
   }
 public static int GetSubMeshIndex(Mesh mesh, int triangleIndex)
     {
         if (mesh.isReadable == false)
         {
             Debug.LogError("You need to mark model's mesh as Read/Write Enabled in Import Settings.", mesh);
             return 0;
         }
 
         int triangleCounter = 0;
         for (int subMeshIndex = 0; subMeshIndex < mesh.subMeshCount; subMeshIndex++)
         {
             var indexCount = mesh.GetSubMesh(subMeshIndex).indexCount;
             triangleCounter += indexCount / 3;
             if (triangleIndex < triangleCounter)
             {
                 return subMeshIndex;
             }
         }
 
         Debug.LogError(
             $"Failed to find triangle with index {triangleIndex} in mesh '{mesh.name}'. Total triangle count: {triangleCounter}",
             mesh);
         return 0;
     }
 }

But this did not give any result because the array is empty