Here’s a reverse sear recipe from America’s Test Kitchen. Their recipes are heavily tested and usually outstanding, although frequently over-complicated. If you don’t want to invest all the time into it, then you can just use their baking instructions and do your own thing for the seasoning. I haven’t heard of using an air fryer for cooking steak, so you’re on your own there. If I had to guess, I’d say it might dry it out a little, so maybe not the best approach.