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 · Competitive PvP
Cover-based shotgun duels testing movement execution and positional prediction in multiplayer.

Execution · Competitive PvP
Territory control through shooter execution and constant prediction of adapting human teams.
Gears of War: Ultimate Edition 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.
Gears of War: Ultimate Edition
Wallbounce movement and gnasher duels demand real hands
Splatoon
Aim, swim-form movement and ink management are constant demands
Splatoon leans a little harder on reads, though the gap is small.
Gears of War: Ultimate Edition
Multiplayer is constant positional mind-games around cover
Splatoon
Human opponents adapt flanks and pushes every match
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Gears of War: Ultimate Edition
Weapon spawns timed and known; spread mildly random
Splatoon
Hidden squids in ink create momentary information gaps
Splatoon leans a little harder on optimization, though the gap is small.
Gears of War: Ultimate Edition
Map control and spawn timing knowledge structure matches
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.