Rigidbody.MoveRotation() Towards an object?

In short: I want an object to follow rotation of another object, but with slight delay (a lag), like it was heavy - How can I do it so that it also detects collision? I know it will be something like Rigidbody.Moverotation( but I have no idea where to get it from there.

EDIT: Scenario: I want an automatic turret to always slowly follow where a First-Person Camera of the palyer is looking. For example, you look to the right - turret is also turning to the right to match camera’s rotation.

Help?

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