head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Optimization · Practiced Mastery
A tactical cover shooter where build crafting and teamwork meet real PvP reads in contested Dark Zone spaces.

Optimization · Practiced Mastery
Planning a raid in advance, then executing it where one mistake kills.
The Division 2 leans Optimization (Practiced Mastery); Tom Clancy's Rainbow Six leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
The Division 2
Cover shooting and positioning demand consistent aim under pressure
Tom Clancy's Rainbow Six
One bullet kills, so entries demand clean aim
The Division 2 leans a little harder on reads, though the gap is small.
The Division 2
Dark Zone and conflict PvP feature real adaptive opponents
Tom Clancy's Rainbow Six
Multiplayer raids add human counterplay
The Division 2 leans a little harder on variance, though the gap is small.
The Division 2
Named item drops and talent rolls add meaningful RNG
Tom Clancy's Rainbow Six
Terrorist placements are unknown until doors open
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
The Division 2
Skill builds and gear set synergies are extensively theory-crafted
Tom Clancy's Rainbow Six
The pre-mission planning phase is the real game
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.