Advanced Blinking Marker Script to show objects position in your game canvas

https://youtu.be/NZwukp7ZhCE

Here is advanced version of blinking marker script that you see in my video above:

using UnityEngine;
using UnityEngine.UI;
using System.Collections.Generic;

public class BlinkingMarker : MonoBehaviour
{
    [Header("Marker Settings")]
    [Tooltip("Tags of objects to track")]
    public string[] tagsToMark;

    [Tooltip("UI prefab for the marker")]
    public GameObject spriteObject;

    [Tooltip("Parent transform for all markers")]
    public RectTransform markersParent;

    private Dictionary<GameObject, GameObject> trackedObjects = new Dictionary<GameObject, GameObject>();
    private Camera mainCamera => Camera.main; // Store the main camera reference

    void Start()
    {
        // Find the main camera on start.  You might need to adjust this if your camera setup is more complex.
        //mainCamera = Camera.main;
        if (mainCamera == null)
        {
            Debug.LogError("Main Camera not found!  Make sure you have a Camera tagged as MainCamera in your scene.");
        }
    }

    void Update()
    {
        // Check for new objects and update existing markers every frame.
        // This is necessary because objects can be spawned and destroyed dynamically.
        UpdateTrackedObjects();
        UpdateMarkerPositions();
    }

    void UpdateTrackedObjects()
    {
        // Find all objects with the specified tags
        foreach (string tag in tagsToMark)
        {
            GameObject[] foundObjects = GameObject.FindGameObjectsWithTag(tag);

            foreach (GameObject obj in foundObjects)
            {
                // If the object is not already being tracked, create a marker for it
                if (!trackedObjects.ContainsKey(obj))
                {
                    CreateMarker(obj);
                }
            }
        }

        // Check for destroyed objects and remove their markers
        List<GameObject> objectsToRemove = new List<GameObject>();
        foreach (var pair in trackedObjects)
        {
            if (pair.Key == null) // Object has been destroyed
            {
                objectsToRemove.Add(pair.Key);
                Destroy(pair.Value); // Destroy the marker
            }
        }

        foreach (GameObject obj in objectsToRemove)
        {
            trackedObjects.Remove(obj);
        }
    }

    void CreateMarker(GameObject targetObject)
    {
        if (spriteObject == null || markersParent == null)
        {
            Debug.LogError("Sprite Object or Markers Parent is not assigned!");
            return;
        }

        if (mainCamera == null)
        {
            Debug.LogError("Main Camera not found!  Make sure you have a Camera tagged as MainCamera in your scene.");
            return;
        }

        GameObject marker = Instantiate(spriteObject, markersParent);
        marker.SetActive(true); // Ensure the marker is active

        trackedObjects.Add(targetObject, marker);
    }

    void UpdateMarkerPositions()
	{
		if (mainCamera == null)
		{
			Debug.LogError("Main Camera not found!  Make sure you have a Camera tagged as MainCamera in your scene.");
			return;
		}

		foreach (var pair in trackedObjects)
		{
			GameObject targetObject = pair.Key;
			GameObject marker = pair.Value;

			if (targetObject != null && marker != null)
			{
				// 1. Convert world position to screen position
				Vector3 screenPosition = mainCamera.WorldToScreenPoint(targetObject.transform.position);

				// 2. Check if the object is in front of the camera
				if (screenPosition.z > 0)
				{
					// 3. Convert screen position to canvas local position
					Vector2 anchoredPosition;
					// For Screen Space - Overlay canvas, pass null as camera
					RectTransformUtility.ScreenPointToLocalPointInRectangle(
						markersParent, 
						screenPosition, 
						null, // Or mainCamera if your canvas is in Screen Space - Camera
						out anchoredPosition
					);

					// 4. Set marker position
					marker.GetComponent<RectTransform>().anchoredPosition = anchoredPosition;
					marker.SetActive(true);
				}
				else
				{
					marker.SetActive(false);
				}
			}
		}
	}
}

To make the marker object interesting, add some animation to it, for example blinking, fading, etc.

I have old version of this script in this post: https://thirteenov.ciihuy.com/blinking-marker-unity-screen-space-marker-overlay-script/