There is nothing wrong with construction lines. Andrew Lumis the famous illustrator wrote books on his method of drawing dubbed “the lumis method” which goes into constructing a head/face or hands from basic shapes and working your way up to the full drawing. In his life and his work he used his own method all the time to draw faces and people.

While I understand not wanting to rely on them anymore for drawing anything your goal should be to intuitively understand the process your using without thought which only comes from practice.