head to head
Neither is simply harder - they are hard in different places. The Elder Scrolls V: Skyrim demands more execution; Victoria 3 demands more reads.

Optimization · Pure Optimization
An open-world RPG mostly about discovering and stacking exploitable progression systems.

Optimization · Pure Optimization
Industrial-era economy sim; pops and markets above all.
The Elder Scrolls V: Skyrim leans Optimization (Pure Optimization); Victoria 3 leans Optimization (Pure Optimization).
The Elder Scrolls V: Skyrim leans clearly harder on execution.
The Elder Scrolls V: Skyrim
Combat is forgiving; aim and timing rarely punish you.
Victoria 3
no reflex
Victoria 3 leans clearly harder on reads.
The Elder Scrolls V: Skyrim
Enemy AI is scripted and exploitable; not adaptive.
Victoria 3
AI scripted, limited adaptation
Victoria 3 leans a little harder on variance, though the gap is small.
The Elder Scrolls V: Skyrim
Loot tables and leveled lists inject mild randomness.
Victoria 3
events, market shocks
Victoria 3 leans clearly harder on optimization.
The Elder Scrolls V: Skyrim
Skill stacking, enchant loops, and exploits are deeply solvable.
Victoria 3
economy, pops, laws 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.