Don't point your elbows straight out to the sides on the dumbbell overhead press.
Every time you raise your arm overhead there's some level of contact of the rotator cuff on the acromion, so there's always some level of impingement with arm elevation. But you don't want excessive contact that causes irritation and inflammation, which can lead to shoulder impingement syndrome. Doing the dumbbell overhead press in the plane of the scapula minimizes the joint stress.
Keep the arms at an angle to the torso, in the scapular plane, not out to the sides. Doing this exercise in the plane of the scapula will create tension in the delts, but decrease joint stress because it's a more natural path of movement.