I’m not sure if the air fryer is the ideal way to make a toasted cheese sandwich. It is a small, hot oven but it has the disadvantages of a powerful fan and deep-sided drawers. It probably took about 15 minutes all told in my effort tonight and I’m not sure it was quicker or any better than toasting a couple of slices of bread, making a cheese sandwich with them and then microwaving the result to finish off the cheese.
Better still is to use a frying pan. The bread can be buttered and lightly fried, sandwiched around cheese and then returned for finishing off. The lower sides of the pan make it easy to get in with a spatula or slice for flipping and I’ve got a “burger press” which can add the compression that helps the melting cheese glue the two halves together.
There are plenty of things the air fryer excels at but, in my experience, the toasted cheese sandwich is not one of them.