This is my suggestion:
Add a toggle in the options to select whether food is required for resting or not. If the player selects that it is required, either the amount of food required per rest or the amount of food available in the world (or both) could change depending on the difficulty or as a separate option.
This would let people who want to manage resources do so and those who don’t want to manage resources avoid it. It would also use a system they already created and so hopefully would not be as much work.
Difficulty options are good and food is already in the game so it's an easy fix. +1 for this suggestion, at least over what we have now.
I hate toggles for every detail. Probably Larian does too. It's like game devs saying "we dont know how the game should play, you figure it out". They should just incorporate everything into difficulty settings. And then lock the settings so that when you run out of food on Hard you're not tempted to switch to Normal to Long Rest whenever you want.
As for the food mechanic specifically, it's not meaningful resource management. There's so much food available you don't have to manage anything, just take all. You're not limited by weight because you can send it to camp, and teleport there with the press of a button. It's just a tedious mini-game before resting. And if you were limited by weight, it would just get annoying because it would only make selling loot more tedious and make you do more trips to traders. I don't understand why they created the food mechanic in the first place, it can never be good resource management.
There are better ways to restrict the frequency of Long Rest which is really the goal here.