head to head
Neither is simply harder - they are hard in different places. Super Mario Odyssey demands more execution; WWF Royal Rumble demands more reads.

Execution · Pure Mechanics
A 3D platformer whose joy lives in tight movement and capture-driven traversal.

Execution · Pure Mechanics
Grapple-timing execution and mashing stamina in arcade wrestling matches.
Super Mario Odyssey leans Execution (Pure Mechanics); WWF Royal Rumble leans Execution (Pure Mechanics).
Super Mario Odyssey leans clearly harder on execution.
Super Mario Odyssey
Precise platforming and capture-move tech ceiling.
WWF Royal Rumble
Grapple timing and button mashing decide every lock-up
WWF Royal Rumble leans clearly harder on reads.
Super Mario Odyssey
No adaptive opponents whatsoever.
WWF Royal Rumble
Human opponents add some habit prediction in versus
WWF Royal Rumble leans a little harder on variance, though the gap is small.
Super Mario Odyssey
Almost no randomness in level design.
WWF Royal Rumble
Little is hidden beyond grapple outcome wobble
Super Mario Odyssey leans clearly harder on optimization.
Super Mario Odyssey
Moon routes and movement tech learnable.
WWF Royal Rumble
Move utility knowledge is a shallow solvable layer
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.