Changing item quantities

So as far as I know, it is currently impossible to change how many you how of a certain item (toolbox, medkit, etc) and I am really curious as to why this is.

Now I've been using Cheat Engine for quite some time now but I am definitely not an expert on this kind of thing so I just wanna know if anyone here knows how this system works and if it would ever be possible to mod items.

i think you can do it, just do like you do for bp dont work?