Wagyu: The fat will render when the meat warms up, and long before it get hot enough to cook.
I sear the wagyu I cook, and that's about it.
Steaks I do at 700f, but low and slow wagyu is of no interest for me so I cannot advise.
Cowards hunt in packs
Strife brings out friends
Injustice brings out decency
but only in the classy people