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
Legendary turn-based strategy of castle economies, hero armies, and tile-perfect logistics.

Optimization · Pure Optimization
A grand strategy 4X where empire optimization carries you through random crises.
Heroes of Might and Magic III leans Optimization (Pure Optimization); Stellaris 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.
Heroes of Might and Magic III
Turn-based; zero dexterity
Stellaris
Real-time pausable with no input precision.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Heroes of Might and Magic III
Human multiplayer adds bluffing; AI is mappable
Stellaris
AI is scripted; multiplayer adds modest adaptation.
Stellaris leans a little harder on variance, though the gap is small.
Heroes of Might and Magic III
Map fog, creature banks, and morale rolls
Stellaris
Galaxy gen, anomalies, and crises vary widely.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Heroes of Might and Magic III
Hero chains, build orders, and combat math are deeply solvable
Stellaris
Empire builds, fleet comps, and economy dominate.
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.