Many things could be done:
Genioplasty
Different techniques exist. Separate the chin and slide it upwards or forward along the cut or move it diagonally and fill the gap (for example with bone graft from the hip).
Chin-Wing
Basically extend the cut from the genioplasty as far back as possible or desired. The mandibular border can be rotated forward counter clockwise or straight along the cut. In my opinion the best indication is a hyperdivergent lower jaw (steep) but a class 1 molar relationship. The counter clockwise rotation will correct the steep mandibular border and stretch soft tissue. But if the jawline is too steep it is sometimes not possible to safely extend the cut all the way back. It is also possible to "bend" the mand. border lateraly. Bone graft is needed in most cases obv.
Jaw-Surgery
Longest timeline. Usually braces months before surgery and after surgery. Surgery first approach exists (no de-compensation before surgery) but I dont really know the indication for this. I assume your bite has to be perfect and both jaws then moved I such a way that the bite remains perfect after surgery. Low margin for error. But other users can help you better with jaw surgery.
But: Your non-existing jawline (your own observation) would not improve by much just with a genioplasty. This is my guess.
