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.

Variance · Systems & Chaos
Turn-based resource management through randomly generated dungeon layouts.

Optimization · Systems & Chaos
Balancing faction meters against random card draws, one binary swipe at a time.
Pokémon Mystery Dungeon: Red Rescue Team leans Variance (Systems & Chaos); Reigns: Her Majesty leans Optimization (Systems & Chaos).
Pokémon Mystery Dungeon: Red Rescue Team leans a little harder on execution, though the gap is small.
Pokémon Mystery Dungeon: Red Rescue Team
Turn-based grid movement - no twitch demands
Reigns: Her Majesty
Swiping left or right is the entire physical demand
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Mystery Dungeon: Red Rescue Team
Wild Pokémon follow simple deterministic AI
Reigns: Her Majesty
Court characters are card scripts, not adapting opponents
Pokémon Mystery Dungeon: Red Rescue Team leans a little harder on variance, though the gap is small.
Pokémon Mystery Dungeon: Red Rescue Team
Random dungeon layouts, items and encounters each run
Reigns: Her Majesty
Card draws and unknown consequences drive each reign's fate
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Mystery Dungeon: Red Rescue Team
Team building, item management and type matchups carry runs
Reigns: Her Majesty
Balancing four faction meters is a learnable solvable system
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.