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 · Pure Mechanics
Pure aim and movement skill tested against adaptive human opponents competing for spawn-cycle dominance.

Execution · Grand Arena
Team-based 5v5 Star Wars starfighter combat with cockpit power management.
Quake III Arena leans Execution (Pure Mechanics); Star Wars: Squadrons leans Execution (Grand Arena).
Quake III Arena leans a little harder on execution, though the gap is small.
Quake III Arena
Rail and rocket aim at speed is the entire game
Star Wars: Squadrons
Drifting, aim, and throttle tricks decide dogfights
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Quake III Arena
Human opponents adapt their routes and timings in direct response
Star Wars: Squadrons
Human pilots in 5v5 bait, juke, and counter-adapt
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Quake III Arena
Spawn locations have mild randomness but are quickly mapped
Star Wars: Squadrons
Full information maps; little randomness
Star Wars: Squadrons leans a little harder on optimization, though the gap is small.
Quake III Arena
Armor and weapon timing routes are learnable and highly leveraged
Star Wars: Squadrons
Power management and loadout meta are solvable layers
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.