Yes, there are definitely things that Larian needs to restrict in here. :P I'm sure they are working on it.
Such as all inventory, other than potions and scrolls can be used in battle, before your action, and only potions and scrolls (that require a bonus action) can be used when you just have a bonus action left. Once action and bonus action have been used, inventory should be locked.
As it shows in your character screen, you can only have 1 melee and one ranged weapon equipped, which is a free action to switch back and forth. Any other weapon which is in your inventory would require a bonus action to switch out with the one already equipped. That would solve the problem with OP's situation.
Food should only be able to be consumed outside of battle. It takes you longer than 6 seconds to eat an apple or a loaf of bread after all. :P