Holy hell there’s a difference between your 4hr events and mine.
4hr 75k 1200m elevation vs 4.5hr 75k 2000m - not too different.
But looking at the power:
IF .69 vs .99
NP 221 vs 249
TSS 200 vs 434 (based on our ftp differences…)
3% anaerobic vs 27% for me (!)
Is there an Amber’ism to describe the multiple ways to skin a cat 
Like boxing: “Everybody’s got a plan until you get punched in the face”.
Course demands can make the spectrum for XCM really broad. Repeatability can be key on singletrack heavy courses where you need to stay on top of the gear to maintain momentum, especially if there are reasonable descents for recovery. In my mind, this is pure xc, that matches the TR XCO model.
Many mtb marathons are more tempo focused however, the profile for yours looks very continuous rolling terrain, with demands perhaps aligned more to the rolling road race.