I haven't had fried chicken in a while now mind you, but both when I was a kid and my family would have leftover KFC, and as an adult in the rare occasion I do get fried chicken, I have always loved it more after it's been sitting overnight in the fridge.
Won't heat that shit in the microwave or nuthin, just eat it straight cold and love it like that.
I've done that often, and it's pretty good. French fries too, you can get one adequate reheat in an air fryer, but it's touchy... a couple of minutes at the temp that works best in your fryer, and nothing more, or they turn into garbage twigs. Still don't finish them and try it again? Garbage twigs. The line between ever so slightly overcrisped, yet still solid, leftover fries and garbage twigs is rather thin.