head to head
Neither is simply harder - they are hard in different places. Disco Elysium demands more optimization; L.A. Noire demands more execution.

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

Optimization · Systems & Chaos
1940s detective procedural built around crime scenes and reading scripted interrogation tells.
Disco Elysium leans Optimization (Pure Optimization); L.A. Noire leans Optimization (Systems & Chaos).
L.A. Noire leans clearly harder on execution.
Disco Elysium
No mechanical inputs of consequence
L.A. Noire
Light shooting and driving, very forgiving
Disco Elysium leans a little harder on reads, though the gap is small.
Disco Elysium
Dialogue partners are scripted, not modeling you
L.A. Noire
Suspects follow fixed scripts, never adapt
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Disco Elysium
Skill checks roll dice with hidden modifiers
L.A. Noire
Interrogation tells and clues hidden until discovered
Disco Elysium leans clearly harder on optimization.
Disco Elysium
Build skills and route choices to pass checks
L.A. Noire
Evidence chains and question choices have fixed correct answers
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.