head to head
Neither is simply harder - they are hard in different places. Fortnite demands more variance; StarCraft demands more optimization.

Execution · Grand Arena
Build-fight battle royale with deep mechanics.

Optimization · Grand Arena
A real-time strategy classic where perfected build orders and mechanical speed decide most matches.
Fortnite leans Execution (Grand Arena); StarCraft leans Optimization (Grand Arena).
Fortnite leans a little harder on execution, though the gap is small.
Fortnite
Build-edit-aim combos punish slow hands
StarCraft
APM and micro control ceiling is huge
Fortnite leans a little harder on reads, though the gap is small.
Fortnite
Box fights are pure adaptive mind games
StarCraft
scouting and predicting human opponent builds
Fortnite leans clearly harder on variance.
Fortnite
Loot drops, storm, item rotations vary
StarCraft
minimal hidden info beyond fog of war
StarCraft leans clearly harder on optimization.
Fortnite
Loadouts, mats economy, rotations solvable
StarCraft
build orders and economy are near-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.