The direction of the story was railroaded in the original, but the player's flexibility in how they approached each mission was definitely not.

HBomberguy did a whole video about how DXHR failed to achieve the same level of freedom of problem-solving that the original did. It's quite good, but also very long. Worth it, IMO.

https://www.youtube.com/watch?v=bgJazjz9ZsA

there's a GDC talk on Youtube where Warren Spector makes that point explicitly. The original was narratively linear but had freedom within the mission gameplay. He considered that vital for the tension of the story. This is also why HR succeeded for me in contrast to Mankind Divided. The 'open world' like approach of the latter sidelined the main story which seemed almost tangential. Which is a problem in many games these days.

https://youtu.be/tffX3VljTtI