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

Optimization · Pure Optimization
A dialogue RPG resolved by stat builds against dice checks.

Optimization · Pure Optimization
An open-world RPG mostly about discovering and stacking exploitable progression systems.
Disco Elysium leans Optimization (Pure Optimization); The Elder Scrolls V: Skyrim leans Optimization (Pure Optimization).
The Elder Scrolls V: Skyrim leans clearly harder on execution.
Disco Elysium
No mechanical inputs of consequence
The Elder Scrolls V: Skyrim
Combat is forgiving; aim and timing rarely punish you.
Disco Elysium leans a little harder on reads, though the gap is small.
Disco Elysium
Dialogue partners are scripted, not modeling you
The Elder Scrolls V: Skyrim
Enemy AI is scripted and exploitable; not adaptive.
Disco Elysium leans clearly harder on variance.
Disco Elysium
Skill checks roll dice with hidden modifiers
The Elder Scrolls V: Skyrim
Loot tables and leveled lists inject mild randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Disco Elysium
Build skills and route choices to pass checks
The Elder Scrolls V: Skyrim
Skill stacking, enchant loops, and exploits 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.