head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Execution · Twitch Chaos
Budget kart racer where Garfield and friends sling lasagna on the track.

Execution · Twitch Chaos
A kart racer where controlled chaos from random items tempers otherwise precise driving skill.
Garfield Kart - Furious Racing leans Execution (Twitch Chaos); Mario Kart 8 leans Execution (Twitch Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Garfield Kart - Furious Racing
Drift timing and hazard dodging
Mario Kart 8
precise drifting and item timing matter
Garfield Kart - Furious Racing leans a little harder on reads, though the gap is small.
Garfield Kart - Furious Racing
Light item mindgames versus humans
Mario Kart 8
minimal, mostly reacting not predicting
Mario Kart 8 leans a little harder on variance, though the gap is small.
Garfield Kart - Furious Racing
Random item rolls swing races
Mario Kart 8
item boxes are heavily randomized
Mario Kart 8 leans a little harder on optimization, though the gap is small.
Garfield Kart - Furious Racing
Track shortcuts and item knowledge
Mario Kart 8
track lines and item strategy solvable
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.