head to head
Neither is simply harder - they are hard in different places. Boxing demands more reads; DOOM (2016) demands more optimization.

Execution · Pure Mechanics
A two-minute test of joystick reflexes and simple punch-trading rhythm.

Execution · Pure Mechanics
Push-forward arena FPS where movement and aim are the whole game.
Boxing leans Execution (Pure Mechanics); DOOM (2016) leans Execution (Pure Mechanics).
DOOM (2016) leans a little harder on execution, though the gap is small.
Boxing
Joystick speed and punch timing decide the two-minute bout
DOOM (2016)
Aim, movement, glory-kill timing all peak.
Boxing leans clearly harder on reads.
Boxing
A human second player can be baited and predicted
DOOM (2016)
Demons scripted attack patterns.
DOOM (2016) leans a little harder on variance, though the gap is small.
Boxing
Nothing hidden or random in the ring
DOOM (2016)
Minimal encounter randomness.
DOOM (2016) leans clearly harder on optimization.
Boxing
Scoring rules are shallow; positioning tricks are quickly learned
DOOM (2016)
Rune and weapon mod picks meaningful.
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.