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

Optimization · Pure Optimization
Dystopian management adventure about a landlord spying on tenants for a totalitarian state.

Optimization · Pure Optimization
The original post-apocalyptic CRPG where character builds solve the wasteland.
Beholder leans Optimization (Pure Optimization); Fallout 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.
Beholder
Simple point-and-click landlord actions
Fallout
Turn-based, no dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Beholder
Tenants follow scripted schedules, not adaptive
Fallout
No adaptive opposition
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Beholder
Tenant events and directives surprise first runs
Fallout
To-hit rolls and random encounters
Fallout leans a little harder on optimization, though the gap is small.
Beholder
Money, time, and blackmail decision routing
Fallout
SPECIAL builds and quest routing are deeply 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.