head to head
Neither is simply harder - they are hard in different places. Borderlands 2 demands more execution; Flotilla demands more reads.

Optimization · Systems & Chaos
Loot-shooter RPG built on gear chasing.

Optimization · Systems & Chaos
A turn-based 3D space tactics game about flanking fleets across randomized adventures.
Borderlands 2 leans Optimization (Systems & Chaos); Flotilla leans Optimization (Systems & Chaos).
Borderlands 2 leans clearly harder on execution.
Borderlands 2
Aim matters but generous hit feel
Flotilla
Turn-based orders, no twitch demand
Flotilla leans clearly harder on reads.
Borderlands 2
Enemies are scripted loot fodder
Flotilla
Versus mode lets you predict human fleet moves
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Borderlands 2
Procedurally generated weapon drops vary
Flotilla
Randomized encounters and loot drive each adventure
Borderlands 2 leans a little harder on optimization, though the gap is small.
Borderlands 2
Skill trees and gear math heavily solved
Flotilla
3D positioning and flanking angles solve battles
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.