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
A flashy arena fighter testing reaction timing and substitution mind-games against humans.
ARMS leans Reads (Competitive PvP); Naruto x Boruto: Ultimate Ninja Storm Connections 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
Naruto x Boruto: Ultimate Ninja Storm Connections
Combo timing and substitution reactions decide exchanges
ARMS leans a little harder on reads, though the gap is small.
ARMS
Whiff-punish games against adapting humans
Naruto x Boruto: Ultimate Ninja Storm Connections
Human opponents bait substitutions and punish habits
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
Naruto x Boruto: Ultimate Ninja Storm Connections
Little hidden beyond occasional support-assist surprises
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
Naruto x Boruto: Ultimate Ninja Storm Connections
Team composition and meter management reward system knowledge
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.