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 · Practiced Mastery
Tests arcade sports timing in a licensed fantasy sport with swingy Snitch catches.

Execution · Competitive PvP
Party sports where light timing and item luck outweigh deep strategy.
Harry Potter: Quidditch World Cup leans Execution (Practiced Mastery); Mario Sports Mix 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.
Harry Potter: Quidditch World Cup
Timing passes, tackles and Snitch chases needs moderate dexterity
Mario Sports Mix
Timing shots and blocks matters but stays party-game forgiving
Mario Sports Mix leans a little harder on reads, though the gap is small.
Harry Potter: Quidditch World Cup
Versus a friend, faking plays adds light prediction
Mario Sports Mix
Human opponents fake passes and shots in versus play
Mario Sports Mix leans a little harder on variance, though the gap is small.
Harry Potter: Quidditch World Cup
Snitch appearances and combo opportunities add swing
Mario Sports Mix
Item drops and special shots inject deliberate chaos
Harry Potter: Quidditch World Cup leans a little harder on optimization, though the gap is small.
Harry Potter: Quidditch World Cup
Special move charging and team choice reward system knowledge
Mario Sports Mix
Shallow team and court knowledge caps quickly
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.