head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Optimization · Pure Optimization
WWII grand strategy: templates, production, and focus paths.

Optimization · Pure Optimization
Tuning interlocking production chains and racing victory-point routes.
Hearts of Iron IV leans Optimization (Pure Optimization); The Settlers 7: Paths to a Kingdom leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Hearts of Iron IV
pausable, micromanagement-heavy
The Settlers 7: Paths to a Kingdom
Slow-paced clicking - no twitch demand
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Hearts of Iron IV
PvP partly, mostly scripted AI
The Settlers 7: Paths to a Kingdom
Multiplayer victory-point races involve anticipating rival paths
Hearts of Iron IV leans a little harder on variance, though the gap is small.
Hearts of Iron IV
focus tree branches, events
The Settlers 7: Paths to a Kingdom
Map resources are fixed and visible after scouting
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Hearts of Iron IV
division templates and production solved
The Settlers 7: Paths to a Kingdom
Production chains and victory-point routing are the whole game
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.