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 round-based tactical shooter decided by aim duels and adapting to humans.

Execution · Pure Mechanics
Pure aim and movement skill tested against adaptive human opponents competing for spawn-cycle dominance.
Counter-Strike 2 leans Execution (Competitive PvP); Quake III Arena leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Counter-Strike 2
Aim, spray control, and movement are the headline skills.
Quake III Arena
Rail and rocket aim at speed is the entire game
Counter-Strike 2 leans a little harder on reads, though the gap is small.
Counter-Strike 2
Five humans constantly adapting peeks, fakes, and timings.
Quake III Arena
Human opponents adapt their routes and timings in direct response
Counter-Strike 2 leans a little harder on variance, though the gap is small.
Counter-Strike 2
Spray RNG and unknown opponent positions add fog.
Quake III Arena
Spawn locations have mild randomness but are quickly mapped
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Counter-Strike 2
Economy, util usage, and map theory are studyable.
Quake III Arena
Armor and weapon timing routes are learnable and highly leveraged
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.