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
Open-world Stone Age action game about hunting and conquering tribal outposts with tamed beasts.

Execution · Practiced Mastery
A cinematic open-world western leaning on shooting feel and atmosphere.
Far Cry Primal leans Execution (Practiced Mastery); Red Dead Redemption 2 leans Execution (Practiced Mastery).
Far Cry Primal leans a little harder on execution, though the gap is small.
Far Cry Primal
Bow aim, melee timing, beast control under pressure
Red Dead Redemption 2
Gunplay and Dead Eye reward aim and timing.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Far Cry Primal
Scripted tribal AI never models the player
Red Dead Redemption 2
Enemies use scripted AI patterns, not adaptation.
Far Cry Primal leans a little harder on variance, though the gap is small.
Far Cry Primal
Wildlife encounters and patrol spawns are random
Red Dead Redemption 2
Some hunting and weather randomness, lightly hidden.
Far Cry Primal leans a little harder on optimization, though the gap is small.
Far Cry Primal
Outpost routes, crafting economy, beast taming order
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.