Deletion Sequence issue

Hi, I have some problem with this code

 public void FormTileIslandArray()
     {    
         ClearIsland();
         
         for( CardAtt.COLORS color = CardAtt.COLORS.RED; color< CardAtt.COLORS.LENGTH; color++ )    
         {
             for( CardAtt.NUMBERS number = CardAtt.NUMBERS.ONE; number< CardAtt.NUMBERS.LENGTH; number++ )
             {
                 SpawnTileIsland( number, color );
             }
         }
     }
     
     public void ClearIsland()
     {
         foreach( GameObject tileIsland in GameObject.FindGameObjectsWithTag("tileIsland") )
         {
             DestroyObject(tileIsland);
         }
     }

The code was suppose to delete away all of the existing TileIsland Gameobjects before going into a Spawn sequence.

However, all of the TileIsland didn't get deleted before going into spawn sequence, so it caused unwanted errors.

I tried Coroutine, and it didn't helped.

TileIsland is only meant to store list of tiles data. The reason that I made TileIslands into GameObjects, was so that I can check their data in the inspector. If I made Tile Island into an ArrayList instead, I don't know how to check what's inside.

Can anyone suggest me an alternative way to solve this? THX in advance.