head to head
Neither is simply harder - they are hard in different places. Motorsport Manager Mobile 2 demands more reads; Portal demands more execution.

Optimization · Pure Optimization
A racing management sim of car development and live pit strategy.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Motorsport Manager Mobile 2 leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Motorsport Manager Mobile 2
No driving - pure strategy, zero twitch
Portal
Portal placement timing modest.
Motorsport Manager Mobile 2 leans clearly harder on reads.
Motorsport Manager Mobile 2
Predicting rival pit and tire strategy mid-race
Portal
No adversary modeling player.
Motorsport Manager Mobile 2 leans clearly harder on variance.
Motorsport Manager Mobile 2
Weather, reliability and incidents add randomness
Portal
Deterministic chambers; no randomness.
Motorsport Manager Mobile 2 leans a little harder on optimization, though the gap is small.
Motorsport Manager Mobile 2
Car development, pit strategy and economy are the game
Portal
Pure puzzle-solving optimization.
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.