head to head
Neither is simply harder - they are hard in different places. Pokémon Sword demands more variance; Portal 2 demands more execution.

Optimization · Pure Optimization
Galar-region Pokémon adding open Wild Area exploration and stadium Dynamax battles.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Pokémon Sword leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Pokémon Sword
Turn-based menus
Portal 2
Portal placement requires some precision but timing is lenient.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Sword
Gym AI is static
Portal 2
No opponent; puzzles are static.
Pokémon Sword leans clearly harder on variance.
Pokémon Sword
Wild Area spawns and raid rolls
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans a little harder on optimization, though the gap is small.
Pokémon Sword
Dynamax timing and team building decide battles
Portal 2
Solving the puzzle's logic IS the entire game.
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.