How would I go about setting an exclusive collision, i.e. floor that only reacts to the player?

How would I go about having the floor only ever act as a physics-based collider for the player character? I can get collision to work so much better using the inbuilt physics, however, some of my other game objects collide with the floor and do not follow their intended actions. The other objects provide randomized obstacle along the Y axis, so “buffer” obstacle will always collide with the floor if the ‘safe zone’ is randomly generated lower down.

You would set up the floor collider on a new layer and the player on a different layer. Then use Edit > Project Settings > Physics to ensure that the floor layer only colliders with the Player layer.