head to head
Neither is simply harder - they are hard in different places. Marvel Snap demands more variance; StarCraft II: Wings of Liberty demands more execution.

Reads · Grand Arena
A fast card game where the snap mechanic makes reads central.

Execution · Grand Arena
Real-time strategy where hands, reads, and build optimization all matter at the top.
Marvel Snap leans Reads (Grand Arena); StarCraft II: Wings of Liberty leans Execution (Grand Arena).
StarCraft II: Wings of Liberty leans clearly harder on execution.
Marvel Snap
No execution component
StarCraft II: Wings of Liberty
APM, macro, micro-control under pressure
StarCraft II: Wings of Liberty leans a little harder on reads, though the gap is small.
Marvel Snap
Snap/retreat decisions are pure opponent psychology
StarCraft II: Wings of Liberty
1v1 ladder vs adaptive humans modeling you
Marvel Snap leans clearly harder on variance.
Marvel Snap
Hidden locations and draws drive swings
StarCraft II: Wings of Liberty
map spawns minor; mostly known
StarCraft II: Wings of Liberty leans clearly harder on optimization.
Marvel Snap
Deck construction and curve still matter
StarCraft II: Wings of Liberty
build orders, economy curves heavily solved
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.