when you press B to open the backpack, the mod gives priority to the backpack that is in the Trinket Slot, if there is no backpack in that slot, it gives priority to the hotbar, if there is no backpack in the hotbar, it gives priority to the backpack that is closest top left of player inventory

It would be interesting if I could open the other backpacks too, and I can imagine a very practical way to do this:
If the hotkey to open the backpack is B, pressing B+2 would open your second backpack (in the case of the screenshot it would be the brown backpack, from hotbar), pressing B+3 would open the silver backpack, B+4 would open the golden backpack, B+5 would open the diamond backpack
and pressing B+1 would open the backpack with the highest priority

I also found a problem: when a backpack is in the Chestplate Slot, the mod does not give it priority, it becomes the last backpack to be opened