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
Territory control through shooter execution and constant prediction of adapting human teams.

Execution · Competitive PvP
Twitch ball control plus constant prediction of human defenders on known maps.
Splatoon leans Execution (Competitive PvP); TagPro 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.
Splatoon
Aim, swim-form movement and ink management are constant demands
TagPro
Ball handling, boosts and juke precision decide grabs
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Splatoon
Human opponents adapt flanks and pushes every match
TagPro
Human defenders adapt to your routes every match
Splatoon leans a little harder on variance, though the gap is small.
Splatoon
Hidden squids in ink create momentary information gaps
TagPro
Maps and power-up timers are fully visible
Splatoon leans a little harder on optimization, though the gap is small.
Splatoon
Weapon kits, map control timing and gear builds reward study
TagPro
Map routes, button plays and power-up timing are studyable
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.