In your first image where you break the item structure down, that is where I would grab the name of the item and store it in the equipped string or array.
In your second image where you remove the index you would first create a check using the display name of the item or a custom tag, to make sure the index being removed from your inventory does not match the items that are equipped (stored inside that string/array).
if you still cannot get it check out this video set on making an inventory system in UE4…
This is what I used but I expanded on it greatly and it works for everything I need. The video is a little dated but it works.