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

Execution · Grand Arena
A Stone-powered tag fighter where Infinity Stone selection and team synergy drive the competitive meta.

Execution · Grand Arena
A weapons-based 3D fighter where Reversal Edge decisions and ring positioning create constant human reads.
Marvel vs. Capcom: Infinite leans Execution (Grand Arena); SoulCalibur VI leans Execution (Grand Arena).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom: Infinite
Infinity Stone tag combos require practiced execution
SoulCalibur VI
Reversal Edge timing and long lethal hit strings require tight execution
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom: Infinite
Stone selection counter-picks and team tendency reads against humans
SoulCalibur VI
Reversal Edge is a pure read-off mechanic against human opponents
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom: Infinite
No RNG; all information is visible
SoulCalibur VI
No RNG; ring position is full information
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom: Infinite
Stone pairing meta and team routing reward structured study
SoulCalibur VI
Soul Charge routes and matchup character knowledge 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.