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 post-nuclear RPG expanded in scope where tagged builds and Gifted-trait optimization dominate.

Optimization · Pure Optimization
A theorycraft-dense ARPG about engineering builds through randomised loot and crafting.
Fallout 2 leans Optimization (Pure Optimization); Path of Exile leans Optimization (Pure Optimization).
Path of Exile leans a little harder on execution, though the gap is small.
Fallout 2
Turn-based AP system makes twitch entirely irrelevant
Path of Exile
Some dodge and reflex play, but build carries fights.
Fallout 2 leans a little harder on reads, though the gap is small.
Fallout 2
All tribal and Enclave enemies run fixed scripted combat routines
Path of Exile
Mobs and bosses are scripted; no adaptation.
Path of Exile leans a little harder on variance, though the gap is small.
Fallout 2
Hidden special encounters and timed events create significant unknown-information space
Path of Exile
Loot, map mods, and crafting outcomes are heavily random.
Path of Exile leans a little harder on optimization, though the gap is small.
Fallout 2
SPECIAL and skill tagging with Gifted trait produce well-known dominant build strategies
Path of Exile
Passive tree, crafting, and economy form near-infinite theorycraft.
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.