re: Food that is difficult to bring back with taste after refrigerating.

Air fryers are wonderful for leftovers and can even make french fries decent again. Most tomato and pasta-based dishes are fine reheated, or eaten cold.

For leftover steak, I usually cut it up into bite-sized pieces and stir-fry it with onions, peppers, and sometimes mushrooms to warm it up. Then serve it with a couple of sunny side up eggs for steak and eggs.

Things like fried fish and chicken are fine left at room temperature overnight and still good the next day.