How to load only assets that needed?

As I work on live wallpaper, I'm trying to use minimum possible memory. Objects in the scene are instantiating and destroying this way:

 public GameObject prefabObject; // is set in Editor
 private GameObject instanceObject;
 
 ....
 
 private void ShowObject()
     {
         if (this.instanceObject == null)
         {
             this.instanceObject = (GameObject)Instantiate(this.prefabObject);
         }
     }
     
     private void HideObject()
     {
         if (this.instanceObject != null)
         {
             Destroy(this.instanceObject);
             this.instanceObject = null;
         }
     }

Also, there are some HD-versions of textures, which I show and hide the same way - by referencing Material in Editor and instantiating it at runtime when needed;

Although it seems not enough, as RAM used by application on a real device is still about 80-90 MBs, just as it was when all resources were instantiated simultaneously. Expected value must be about a half of it. Also, as all resources still always loading (when only few of them is really used), it obviously takes longer time to load.

How can I load only those assets that I really going to show, but still have strict references to resources to load it when needed?