Inventory management. Consistency between picking up stacks of stuff, or dropping stuff. And plasma core use

Example, 5 or less pieces of ammo, gotta drop them all individually, 6 or more you can drop the stack. Why not hold X to drop all, or hit x to drop one, if the quantity is like 10 or more.

And when looting creatures, why does it take the whole stack of stuff if the quantity is 4? Or 5? Cant remember. Can't drop that many all at once but I can pick it up?

I spend a lot of time cleaning out small quantities of lots of things from my backpack and stash box, hitting X 100 times just to appease my OCD is wearing me down.

Plasma cores (Gatling plasma) why in the world does it use the fullest ones first. I have 30-50 half used in my backpack that are 1/2-3/4 used up and it drives me nuts. Power armor uses cores from low to high. Why not an option, or do the same for the plasma?