head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Practiced Mastery
Timing-based swordplay over a solvable stance-and-loadout system in an authored world.

Execution · Practiced Mastery
An action adventure rewarding combat timing against scripted boss patterns.
Ghost of Tsushima: Director's Cut leans Execution (Practiced Mastery); God of War Ragnarok leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Ghost of Tsushima: Director's Cut
Parry and stance timing carry duels on harder difficulties
God of War Ragnarok
Parry timing and combo execution in combat
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Ghost of Tsushima: Director's Cut
Enemies telegraph from fixed scripts, never model you
God of War Ragnarok
Bosses use fixed movesets
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Ghost of Tsushima: Director's Cut
Open world is authored; little meaningful randomness
God of War Ragnarok
Negligible randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Ghost of Tsushima: Director's Cut
Stance matchups, charms and gear form a solvable system
God of War Ragnarok
Build choices and moveset mastery solve bosses
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.