ACE OF ACES: Can be pretty tough, especially on some of the later missions.
The Highest Achiever: Certainly a pain but, made easier by the fact that multiplayer and VR medals are included.
Bird of Prey: Some of the requirements to spawn the enemy aces will test your patience.
Last One Flying: Winning in Battle Royal can certainly be challenging depending on skill level.
These four are the ones that jumped out at me going back through the list as difficult due to skill dependency.
But the hardest by far, by far... is finding the motivation to grind out 40 000 000 MRP. You can unlock everything at around 32 000 000 MRP so, forty million is just overkill from whoever made this trophy list.
The 76 500km distance trophy is another big grind but, that's rubber band-able.