head to head
Grand Theft Auto: San Andreas asks more than Red Dead Redemption 2, and the gap is optimization.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Execution · Practiced Mastery
A cinematic open-world western leaning on shooting feel and atmosphere.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Red Dead Redemption 2 leans Execution (Practiced Mastery).
Red Dead Redemption 2 leans a little harder on execution, though the gap is small.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Red Dead Redemption 2
Gunplay and Dead Eye reward aim and timing.
Red Dead Redemption 2 leans a little harder on reads, though the gap is small.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Red Dead Redemption 2
Enemies use scripted AI patterns, not adaptation.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Red Dead Redemption 2
Some hunting and weather randomness, lightly hidden.
Grand Theft Auto: San Andreas leans clearly harder on optimization.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
Red Dead Redemption 2
Loadouts and routes solvable but loose.
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.