AngleAxis or Lerp: change both rotation and speed?

Hi,

I would like to rotate around an object, with AngleAxis it works well but I can't (I think) modify the speed of the rotation, and with a lerp, the negative value does not work with my code, it keeps on rotating, and I don't know how to ask the rotation to start from one specific side (if I want the rotation to rotate from the left, or from the right of the object).

Is there a way to do both things with one of these methods? Rotate and choose the side of rotation, and rotate with a specific speed?

Here is the code :

 //#1
 target.localRotation = Quaternion.AngleAxis(170, Vector3.up);
 //-170 works well, but no indication about speed
     
 //#2    
 _y = 170;//-170 keeps on rotating
 float lerp = Mathf.Lerp(target.localEulerAngles.y, _y, Time.deltaTime * 3);
 target.localEulerAngles = new Vector3(0, lerp, 0);

Thanks