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
A Crash Bandicoot party collection of competitive arena minigames for up to four players.

Execution · Twitch Chaos
Item-luck kart racing with a creation suite bolted on.
Crash Bash leans Execution (Competitive PvP); LittleBigPlanet Karting leans Execution (Twitch Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Crash Bash
Minigame timing, mashing, and dodging decide most rounds
LittleBigPlanet Karting
Drifting and weapon timing decide most races
Crash Bash leans a little harder on reads, though the gap is small.
Crash Bash
Human rivals in versus minigames can be baited
LittleBigPlanet Karting
Human racers add light prediction in item battles
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Crash Bash
Item drops and arena randomness swing rounds
LittleBigPlanet Karting
Random item pickups swing positions constantly
LittleBigPlanet Karting leans a little harder on optimization, though the gap is small.
Crash Bash
Light minigame strategies, quickly learned
LittleBigPlanet Karting
Track lines and shortcut knowledge give a modest edge
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.