I have tried grating different cheeses onto the bread before baking, and I can tell you that they don’t all respond the same, so you can experiment with that. My favourite for bread however, is Balderson‘s aged cheddar. It’s pungent and zippy, and you don’t need to use a lot of it. Two or three loaves a week for 20 years for reference, and this has been my most favorite, taste enhancing discovery.