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

Execution · Practiced Mastery
Careful climbing execution and route planning where a single mistimed grab undoes everything.

Execution · Pure Mechanics
An endless runner testing reflexes dodging obstacles at accelerating speed.
Peak leans Execution (Practiced Mastery); Subway Surfers City leans Execution (Pure Mechanics).
Subway Surfers City leans a little harder on execution, though the gap is small.
Peak
Stamina-managed grip timing - one slipped input drops the whole climb
Subway Surfers City
Swiping to dodge obstacles at speed is the whole game
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Peak
Co-op against a mountain, no adaptive opponent
Subway Surfers City
No opponent; an endless solo runner
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Peak
Daily map rotation and item spawns shuffle each ascent
Subway Surfers City
Obstacle patterns are procedurally generated each run
Peak leans a little harder on optimization, though the gap is small.
Peak
Routing the wall and rationing items decides summit attempts
Subway Surfers City
Upgrade choices and pickup routing improve high scores
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.