Make a backup of your project before following please.

Copy the video below, then save the S_ConsumableDetails and then play in editor, this may take a while to load.

Once the player character loads into the game you can exit play in editor, now save all in the content browsers and restart the project.

Add the highlighted nodes shown in the image below, location at the top of the image.

You can now tick on Do Not Remove After Empty in the ItemList in the Consumable Details and the item will remain when 0 uses remain. Please not this does not effect stackable items.