Comparing lerping quaternion

2d top down game. I want my transform to first rotate and face the target position and then move towards it. I got the rotation towards the target position done. It works great. But i need a way to set a bool when the rotation is finished, or finished enough. I tried comparing the quaternions or using quaternion.angle to see if i got a good result but it never arrives. How can i make it so that the bool sets to false when the rotation is 'good enough'?

Ps. i dont want to set a duration for the lerp, i want it to move at a constant speed so that the fewer the angles to rotate, the shorter time it takes.

 if (Input.GetMouseButtonDown (0)) {
                         target = Camera.main.ScreenToWorldPoint (Input.mousePosition);
                         rotateToTarget = true;
                 }
 
                 if (rotateToTarget == true && target != null) {                                
             
                         targetRotation = Quaternion.LookRotation (transform.position - target, Vector3.forward);
                         targetRotation.x = 0.0f;
                         targetRotation.y = 0.0f;
             
                         player.transform.rotation = Quaternion.Slerp (transform.rotation, targetRotation, Time.deltaTime * rotationSpeed);    
                         print (player.transform.eulerAngles + " --> " + targetRotation.eulerAngles);
 
                         if (player.transform.rotation == targetRotation) {
                                 rotateToTarget = false;
                                 travelToTarget = true;
                                 print ("rotation finished");
                         }            
                 }