I'm not an authenticity autist but this is what my friends and I came up with:
Thin sliced ribeye
Provolone is tradition, Whiz is for tourists, white American is acceptable. Some people are trying to make sharp cheddar a thing but I think that is too much of a departure
Grilled onions. I literally don't know anybody who orders one without onions, I think it must be a meme or something not to
The only other acceptable toppings are optional: mushrooms and green peppers
It's weird how people get about their regional foods. Like Chicago's autism about ketchup on hot dogs. Nigga just get it how you want it