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
Combined-arms multiplayer shooter famous for map-altering levolution moments and 64-player conquest.

Execution · Competitive PvP
Shot-timing execution and play-reading against human defensive schemes.
Battlefield 4 leans Execution (Competitive PvP); NBA 2K18 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.
Battlefield 4
Gunplay, vehicle mastery, and movement under fire
NBA 2K18
Shot timing and stick handles decide possessions
NBA 2K18 leans a little harder on reads, though the gap is small.
Battlefield 4
Human teams adapt to flanks and levolution chokes
NBA 2K18
Online, baiting defenders and reading schemes is constant
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Battlefield 4
Map-altering events and spawns inject noise
NBA 2K18
Shot RNG and physics bounces add measured noise
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Battlefield 4
Loadout tuning and objective rotation knowledge
NBA 2K18
Roster builds, playbooks and matchup hunting 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.