May I ask if anyone has made a more systematic equipment. It is possible to compare the items in the backpack with the items already equipped on the body.
Welcome back!
You’ll have to give us some more info 
What is “systematic equipment”? How do you want to compare items an why would their container (backpack, equipment) matter?
If you want to compare item stats there are already videos about it. (I haven’t watched the whole thing but it is the result of a single search)
My advice is - research the topic, start implementing it and come up with more concrete questions we can help you with.