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-ended needs-and-money system that rewards efficient scheduling.

Optimization · Systems & Chaos
Quest-driven life management testing light scheduling and need optimisation.
The Sims leans Optimization (Pure Optimization); The Sims Medieval leans Optimization (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
The Sims
Clicking menus has no physical ceiling
The Sims Medieval
Point-and-click commands, hands irrelevant
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
The Sims
Sims run need-driven scripts, not minds
The Sims Medieval
Sims follow needs simulation, not adaptive minds
The Sims Medieval leans a little harder on variance, though the gap is small.
The Sims
Event rolls add flavour, all quickly mapped
The Sims Medieval
Quest events and sim moods add mild randomness
The Sims leans a little harder on optimization, though the gap is small.
The Sims
Need scheduling, career grinding and money loops are solvable
The Sims Medieval
Quest approach choice and responsibility scheduling 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.