There has been talk of being able to drop backpacks but the managing of separates inventory spaces would be too much of a hassle to manage.
Terraria has a feature in which you tag items in your inventory to keep and then pushing a “drop all” button drops everything but the tagged items. This makes it easy to loot and drop stuff off.
Similar to the auto pickup list but this would be a Do Not Auto Drop list.
There could be two levels - Keep and Combat Drop
Keep would let you easily loot and drop off anything you don’t want to carry with you. Tags things like a few water bottles, gas mask, and tools as Keep to carry them around. All wore items would be tagged as Keep automatically. Used by Drop All key.
Combat Drop could be added to any item that is tagged keep. The Combat Drop key drops all items as in Drop All but also includes combat drop tagged items. This could include backpacks and other encumbrance items that you might want to drop to fight and then pick up later; or drop for extra speed to escape.