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.

Optimization · Pure Optimization
Growing a floating base by solving resource chains and research order against scripted ocean threats.

Optimization · Systems & Chaos
Managing a survivor community's economy and risk under permadeath randomness.
Raft leans Optimization (Pure Optimization); State of Decay 2 leans Optimization (Systems & Chaos).
State of Decay 2 leans a little harder on execution, though the gap is small.
Raft
Shark hook-attacks require minimal timing
State of Decay 2
Combat is forgiving; stealth and swings need modest timing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Raft
Shark and seagull AI are scripted with no player modelling
State of Decay 2
Zombies and hostile NPCs follow randomised scripts
State of Decay 2 leans a little harder on variance, though the gap is small.
Raft
Island loot tables and resource drift introduce randomness
State of Decay 2
Permadeath, infestations and survivor traits randomise each community
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Raft
Raft expansion, food chains, and research order are solvable systems
State of Decay 2
Base building, resource routing and survivor management drive survival
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.