Most block cheeses with a good fat and moisture content will melt well when shredded off the block right before you intend to use it. The pre-shredded or pre-sliced stuff has additives like starch in and on it to stop it from sticking together in the package and melting during transit, which prevents a good melt. Get yourself a cheap rotary shredder from Amazon (they’re like $20, mine never stays clean because I use it like every other day) and see for yourself.