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
Sandbox crime playground spanning shooting, driving, and a persistent online economy.

Execution · Competitive PvP
Arcade wrestling that tests reversal timing and little else by design.
Grand Theft Auto V leans Execution (Practiced Mastery); WWE 2K Battlegrounds 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.
Grand Theft Auto V
Driving and shooting demand decent inputs.
WWE 2K Battlegrounds
Button-mash combos and reversal timing set the pace
WWE 2K Battlegrounds leans a little harder on reads, though the gap is small.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
WWE 2K Battlegrounds
Human opponents add light reversal mind games
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Some mission and lobby randomness.
WWE 2K Battlegrounds
Power-ups and interactive arenas inject party chaos
Grand Theft Auto V leans a little harder on optimization, though the gap is small.
Grand Theft Auto V
Heists, money loops, builds learnable.
WWE 2K Battlegrounds
Shallow systems - move knowledge helps a little
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.