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 break-and-boost JRPG carried by job-routing and party-composition planning.

Optimization · Pure Optimization
Plannable type-matchup progression through two regions of fixed trainers.
Octopath Traveler leans Optimization (Pure Optimization); Pokémon SoulSilver Version leans Optimization (Pure Optimization).
Octopath Traveler leans a little harder on execution, though the gap is small.
Octopath Traveler
Turn-based, no input demand
Pokémon SoulSilver Version
Menu-driven battles have no physical component
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Octopath Traveler
Scripted enemies
Pokémon SoulSilver Version
Trainer AI is scripted; human battles are an optional sideline
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Octopath Traveler
Hit, crit, and break rolls
Pokémon SoulSilver Version
Catch rates, crits and encounters are bounded randomness
Octopath Traveler leans a little harder on optimization, though the gap is small.
Octopath Traveler
Job, break-boost, party routing deeply rewarded
Pokémon SoulSilver Version
Team building against known gyms is fully plannable
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.