Japanese beef is always a challenge and many believe fatty beef is healthy and it is in comparison to the fats in the US beef or for that matter the European fats, and not all fats are the same: https://mesubim.com/2015/11/05/conjugated-linoleic-acid-cla/

Cooking beef can be done a few ways and at home, sous vide work best and then coloring the beef in a pan. The reason this works so well is Japanese wagyu is so intense on flavor, it takes unlike any other beef but if you scorch it, which many do, it will carmelize and it should but too much high heat will spoil the texture.