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 · Grand Arena
An extraction shooter where scavengers dodge killer machines and rival squads for loot.

Execution · Grand Arena
Build-fight battle royale with deep mechanics.
ARC Raiders leans Execution (Grand Arena); Fortnite leans Execution (Grand Arena).
Fortnite leans a little harder on execution, though the gap is small.
ARC Raiders
Gunplay and movement under machine fire
Fortnite
Build-edit-aim combos punish slow hands
Fortnite leans a little harder on reads, though the gap is small.
ARC Raiders
Rival squads ambush, bait, and adapt
Fortnite
Box fights are pure adaptive mind games
ARC Raiders leans a little harder on variance, though the gap is small.
ARC Raiders
Loot spawns and unknown player positions
Fortnite
Loot drops, storm, item rotations vary
Fortnite leans a little harder on optimization, though the gap is small.
ARC Raiders
Loadout economy and map knowledge compound
Fortnite
Loadouts, mats economy, rotations solvable
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.