head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Practiced Mastery
Cornering execution over memorisable circuits, with light prediction in wheel-to-wheel multiplayer.

Execution · Practiced Mastery
Tests racing-line discipline and upgrade economy management on fixed real-world circuits.
Grid 2 leans Execution (Practiced Mastery); Real Racing 3 leans Execution (Practiced Mastery).
Grid 2 leans a little harder on execution, though the gap is small.
Grid 2
Car control through corners is the entire moment-to-moment test
Real Racing 3
Braking points and racing lines are pure motor skill
Grid 2 leans a little harder on reads, though the gap is small.
Grid 2
Online wheel-to-wheel adds light positional prediction
Real Racing 3
Time-shifted opponents are recordings, not adapting minds
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grid 2
Tracks are fixed and fully visible
Real Racing 3
Tracks are licensed and fully fixed
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Grid 2
Racing lines, braking points and car selection are studyable
Real Racing 3
Car upgrades and the monetised economy demand managing
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.