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 · Practiced Mastery
Refined loot shooter with skill-tree builds.

Execution · Twitch Chaos
Dodging under fire while leveraging deep item knowledge against run RNG.
Borderlands 3 leans Optimization (Practiced Mastery); The Binding of Isaac: Afterbirth+ leans Execution (Twitch Chaos).
The Binding of Isaac: Afterbirth+ leans a little harder on execution, though the gap is small.
Borderlands 3
Tighter gunplay than predecessors
The Binding of Isaac: Afterbirth+
Dodging bullet patterns while aiming tears is constant
Borderlands 3 leans a little harder on reads, though the gap is small.
Borderlands 3
Enemies scripted, no adaptive opponent
The Binding of Isaac: Afterbirth+
Enemies are random or scripted, never adaptive
The Binding of Isaac: Afterbirth+ leans a little harder on variance, though the gap is small.
Borderlands 3
Weapon rolls and anointments randomize
The Binding of Isaac: Afterbirth+
Item pools, room layouts and pickups define each run
Borderlands 3 leans a little harder on optimization, though the gap is small.
Borderlands 3
Skill trees, anointments, gear math deep
The Binding of Isaac: Afterbirth+
Encyclopedic item synergy knowledge converts variance into wins
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.