head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Competitive PvP
A crossover anime arena fighter pitting Shonen Jump heroes against each other.

Execution · Competitive PvP
An anime arena fighter testing team-switch timing and counter prediction against humans.
Jump Force leans Execution (Competitive PvP); One Piece: Burning Blood 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.
Jump Force
3D arena combos with generous tracking
One Piece: Burning Blood
Combo timing and guard breaks need moderate hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Jump Force
Human opponents force guard-break guessing
One Piece: Burning Blood
Human opponents bait switches and counters constantly
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Jump Force
Full information arena duels
One Piece: Burning Blood
Full-information arena with no hidden state
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Jump Force
Team picks and awakening meter management
One Piece: Burning Blood
Team composition and Devil Fruit matchups 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.