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
An open-world shooter-RPG won by perk routing and weapon mod optimization.

Optimization · Practiced Mastery
A darkly comic action game where you herd colour-coded minion hordes as an evil overlord.
Fallout 4 leans Optimization (Pure Optimization); Overlord 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.
Fallout 4
FPS aiming, VATS softens demand
Overlord
Sweeping minion hordes takes modest dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout 4
Scripted enemy AI
Overlord
Scripted heroes and creatures
Fallout 4 leans a little harder on variance, though the gap is small.
Fallout 4
Loot and legendary rolls
Overlord
Fixed level design
Fallout 4 leans a little harder on optimization, though the gap is small.
Fallout 4
Perks, settlement, weapon mod planning
Overlord
Minion type usage and upgrade economy reward planning
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.