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.

Execution · Practiced Mastery
Tight platforming execution against fixed boss patterns with a solvable upgrade route.

Execution · Pure Mechanics
Physics-balance execution refined over thousands of attempts on fixed tracks.
Mega Man X3 leans Execution (Practiced Mastery); Trials HD leans Execution (Pure Mechanics).
Trials HD leans a little harder on execution, though the gap is small.
Mega Man X3
Dash-jump precision and boss dodging demand tight inputs
Trials HD
Throttle balance and weight shifts demand frame-tight physical control
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man X3
Mavericks cycle fixed attack patterns
Trials HD
Solo against static obstacle courses
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man X3
Nothing random - every pickup and enemy is placed
Trials HD
Tracks are identical every single attempt
Mega Man X3 leans a little harder on optimization, though the gap is small.
Mega Man X3
Weapon-order and upgrade routing is a known solved sequence
Trials HD
Finding the optimal line through each obstacle rewards study
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.