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
Chess-style positioning where every capture becomes an action duel you must win by hand.

Execution · Practiced Mastery
A team shooter where aim and positioning against human opponents controls the map.
Archon leans Execution (Practiced Mastery); Splatoon 2 leans Execution (Practiced Mastery).
Splatoon 2 leans a little harder on execution, though the gap is small.
Archon
Contested squares resolve in real-time arena combat you must pilot
Splatoon 2
aim and movement decide ink battles
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Archon
Human opponents bait piece trades and combat habits
Splatoon 2
predicting human opponent positioning
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Archon
Luminosity cycle is fully visible; little hidden information
Splatoon 2
weapon and map rotation randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Archon
Chess-like positioning and piece matchups reward calculated play
Splatoon 2
loadout and turf strategy solvable
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.