If recoil is of zero concern, a 7mm x 180 gr vld at lotsa fps is unbeatable IMO. But not required to kill stuff at 750 yards. But the 6.5 is easier to shoot well. Barrel life will never be a design factor to me. Another upside is the current golden era of 6.5 and 7mm bullets.
And optics 😊

I do not entertain hypotheticals. The world itself is vexing enough. -- Col. Stonehill