head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
Deep tactical build crafting and elemental combo solving across set-piece turn-based encounters.

Optimization · Pure Optimization
A break-and-boost JRPG carried by job-routing and party-composition planning.
Divinity: Original Sin II - Definitive Edition leans Optimization (Pure Optimization); Octopath Traveler leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Divinity: Original Sin II - Definitive Edition
Turn-based combat removes any physical ceiling
Octopath Traveler
Turn-based, no input demand
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Divinity: Original Sin II - Definitive Edition
Optional PvP arena aside, AI follows mappable behaviour
Octopath Traveler
Scripted enemies
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Divinity: Original Sin II - Definitive Edition
Initiative rolls, random loot and unknown encounters add spice
Octopath Traveler
Hit, crit, and break rolls
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Divinity: Original Sin II - Definitive Edition
Build synergies, surface combos and positioning are deeply solvable
Octopath Traveler
Job, break-boost, party routing deeply rewarded
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.