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

Execution · Competitive PvP
A chaotic arena fighter built around item combos and stage interaction.

Execution · Competitive PvP
Territory control through shooter execution and constant prediction of adapting human teams.
Power Stone 2 leans Execution (Competitive PvP); Splatoon leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Power Stone 2
fast combo execution and item usage
Splatoon
Aim, swim-form movement and ink management are constant demands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Power Stone 2
reading human opponents in free-for-all combat
Splatoon
Human opponents adapt flanks and pushes every match
Power Stone 2 leans a little harder on variance, though the gap is small.
Power Stone 2
item spawns and stage hazards random
Splatoon
Hidden squids in ink create momentary information gaps
Splatoon leans a little harder on optimization, though the gap is small.
Power Stone 2
item combination knowledge and stage control
Splatoon
Weapon kits, map control timing and gear builds reward study
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.