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

Optimization · Pure Optimization
Deep hex-battle build optimization with dice variance layered over every action.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Blackguards 2 leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Blackguards 2
Hex-grid turns carry no physical demand
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.
Blackguards 2
Enemy AI follows fixed tactical logic
Portal 2
No opponent; puzzles are static.
Blackguards 2 leans clearly harder on variance.
Blackguards 2
Dark Eye dice rolls swing individual actions
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans a little harder on optimization, though the gap is small.
Blackguards 2
Build planning and battlefield manipulation are the deep solvable core
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.