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 · Practiced Mastery
A real-time RPG carried by ascension-grid routing and magic crafting.

Optimization · Practiced Mastery
The sequel adds minion mounts and an evil empire to corral with your goblin hordes.
Final Fantasy XV leans Optimization (Practiced Mastery); Overlord II leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy XV
Real-time combat, modest input demand
Overlord II
Minion sweeps plus mounts need moderate control
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy XV
Scripted enemies
Overlord II
Scripted empire enemies
Final Fantasy XV leans a little harder on variance, though the gap is small.
Final Fantasy XV
Loot and ascension variance
Overlord II
Deterministic encounters
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy XV
Ascension grid, magic crafting, party planning
Overlord II
Minion management and domination choices are solvable
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.