head to head
Neither is simply harder - they are hard in different places. Mario Kart DS demands more variance; Rocket League demands more reads.

Execution · Pure Mechanics
The first online Mario Kart, infamous for the execution-heavy snaking technique dominating play.

Execution · Pure Mechanics
Mechanical car-soccer where execution is the ceiling.
Mario Kart DS leans Execution (Pure Mechanics); Rocket League leans Execution (Pure Mechanics).
Rocket League leans clearly harder on execution.
Mario Kart DS
Snaking demands relentless precise drift inputs
Rocket League
Aerials, flicks, dribbles, pure mechanical ceiling
Rocket League leans clearly harder on reads.
Mario Kart DS
Online opponents punish predictable lines
Rocket League
Rotations and 50-50 reads against humans
Mario Kart DS leans clearly harder on variance.
Mario Kart DS
Item RNG decides tight finishes
Rocket League
Almost deterministic physics
Mario Kart DS leans clearly harder on optimization.
Mario Kart DS
Kart stats, lines, and snaking routes
Rocket League
Training routines, rotation theory
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.