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.

Reads · Competitive PvP
A 3D arena fighter where extendable-arm punches curve mid-flight in PvP duels.

Execution · Competitive PvP
Sony's mascot brawler where only Super attacks score kills, making meter management the whole game.
ARMS leans Reads (Competitive PvP); PlayStation All-Stars Battle Royale 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.
ARMS
Curving punches and dodge timing
PlayStation All-Stars Battle Royale
Combo routes into Super meter need decent but modest hands.
ARMS leans a little harder on reads, though the gap is small.
ARMS
Whiff-punish games against adapting humans
PlayStation All-Stars Battle Royale
Super-only kills make baiting human opponents the core decision.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
ARMS
Minor stage and item randomness
PlayStation All-Stars Battle Royale
Items and four-player chaos add mild randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
ARMS
Arm loadout counters and matchup study
PlayStation All-Stars Battle Royale
Meter-build efficiency per character is the solvable layer.
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.