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

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

Optimization · Pure Optimization
Remake of Gaiden with dual protagonists and explorable dungeons.
Disco Elysium leans Optimization (Pure Optimization); Fire Emblem Echoes: Shadows of Valentia leans Optimization (Pure Optimization).
Fire Emblem Echoes: Shadows of Valentia leans a little harder on execution, though the gap is small.
Disco Elysium
No mechanical inputs of consequence
Fire Emblem Echoes: Shadows of Valentia
Turn-based menus only
Disco Elysium leans a little harder on reads, though the gap is small.
Disco Elysium
Dialogue partners are scripted, not modeling you
Fire Emblem Echoes: Shadows of Valentia
Scripted enemies on both routes
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
Fire Emblem Echoes: Shadows of Valentia
Hit RNG plus dungeon encounters
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
Fire Emblem Echoes: Shadows of Valentia
Dual-army routing and class promotions
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.