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.

Execution · Competitive PvP
Tests shot timing and faking out human defenders amid item-driven chaos.

Execution · Competitive PvP
Tests trajectory aim and turn planning against human targets amid crate luck.
Mario Strikers Charged leans Execution (Competitive PvP); Worms: Ultimate Mayhem 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.
Mario Strikers Charged
Timing tackles, charged shots and goalie deflections needs quick hands
Worms: Ultimate Mayhem
3D grenade arcs and ninja-rope control reward practiced aim
Mario Strikers Charged leans a little harder on reads, though the gap is small.
Mario Strikers Charged
Versus humans, faking shots and baiting tackles drives goals
Worms: Ultimate Mayhem
Predicting a human's target priorities shapes each turn
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Strikers Charged
Items and stage hazards inject swingy chaos into matches
Worms: Ultimate Mayhem
Crate drops, wind and terrain chaos swing rounds
Worms: Ultimate Mayhem leans a little harder on optimization, though the gap is small.
Mario Strikers Charged
Captain abilities and team builds reward knowing the systems
Worms: Ultimate Mayhem
Weapon economy and positioning are plannable each turn
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.