So, I checked where am I decreasing and it was the crafting result slot class, which I just used without editing it.
this.addSlotToContainer(new SlotCrafting(playerInventory.player, this.craftMatrix, this.craftResult, 0, 134, 48));
OK, so I need to make my own version of that class, I see it now
I'll do it right now and I'll write if it works