Which nonsurgical procedure can help me achieve a more defined jaw line? (photo)

Thank you for sharing your question and posting your photo. From the photograph it appears that thread lifting followed by placement of PDO threads would improve your jawline. See an experienced oculofacial surgeon for consultation and guidance.
Good luck,

For a more defined jawline to strengthen your profile (and help prevent the dreaded jawline "jowl" sagging), we use injectable fillers like Revanesse Versa - a filler known to limit swelling and give subtle, soft enhancements - or Radiesse. Using a cannula to limit pain and swelling, we inject on the bone in strategic points to get more lift and shaping, resulting in a more contoured lower face and defined, structured jawline. I would suggest getting a formal evaluation with a facial sculpting expert. Best, Dr. Emer

Simplest suggestion would be the use of a robust HA filler to tighten and define the jawline, which would also secondarily tighten somewhat the double chin issue. And using a robust filler to enhance and masculinize chin projection would likewise not only greater harmony between the projections of the nose, lips and chin in profile, but would also contribute to diminishing the double chin issue. No surprise with your disappointment with Coolsculpting, as most of these bells and whistles devices, like the RF and ultrasound devices (and even the threads) are supported far more by social media and marketing hype than hard science. Sorry. And you would be courting similar disappointment with the other gizmos you mentioned. You would be wise to make certain to consult an experienced board certified cosmetic dermatologist. Hope this helps.