The hot bar has 10 slots.
We have 12 F keys.
So using those, we could have 120 slots.
More then enough. Items also should be in those slots instead of specific slots in the inventory, unless they are tools. Consumables should be in the hot bar, or at least have a specific key to them. Most like in many MMO's.
I do understand of the "logic" of putting a consumable in the hands and then use it, but this can also be done with some twist to the effect of motion of the hands. If we are carring 1 or 2 items, the hands could go down pick the consumable, do the action and then back to carring the previous items that were carried.