How to change velocity directly to a certain speed while keeping the collide direction?

I have a falling object colliding with a "Power Cube". This cube needs to get the velocity of the other rigidbody on collision and change the velocity of that object directly to a defined speed in a variable boostSpeed, while still keeping the same bounce direction as how a rigidbody would handle this.

I came up with this code but its not working correctly for me:

 public class PowerCube : MonoBehaviour {
     public float boostSpeed;
 
     void OnCollisionEnter(Collision other) {
         // Power Cube actions
         other.rigidbody.velocity = other.rigidbody.velocity * boostSpeed;
     }
 }

This will increase the velocity but based on the current velocity of the object. I want all objects that collide with the power cube have the same velocity speed after they collide, but still in the direction how a normal rigidbody would respond. How can I do this?