Struggling with double chin regardless of weight. What can I do to fix it? (Photo)

From your photo it appears that you are an excellent candidate for liposuction of the area. I can't comment on the price in your area, however a local Plastic Surgeon can provide you with that.

There are various options depending on your anatomy, how much correction you want, and what kind of downtime/cost you are OK with.
Without a full side view of your face it is difficult to say for certain, but it looks to me like your chin might be weak. Moving the chin forward can help improve the fullness under your neck. Liposuction of the submental/jawline area can be performed at the same time to further improve the area. In some cases this is all that needs to be done.
If you want the sharpest neck possible, a deep necklift is a better option. This allows me to go after not only the fat in your neck, but prominent glands and muscles. In some cases a chin implant may also be needed at the same time.

"For a double chin, InMode FaceTite with VASERlipo would give you the best result.

With significant neck sagging you would need a facelift / neck lift with muscle tightening (platysmaplasty). At the same time, I would recommend lasers (Fraxel, CO2, Halo, or Erbium) and microneedling RF (Fractora, Morpheus8, PiXel8, Intensif) to improve the crepey skin and wrinkles. Overall, the neck can be treated with a combination approach:

1. Microneedling and laser treatments for texture
2. Botox, Dysport, Xeomin or Jeuveau to help platysmal bands
3. Intensif, Fractora, PiXel8, or Morpheus8 microneedling RF for crepey skin and lifting
4. Injectable fillers like Belotero, Restylane Silk, Versa, and Juvederm Volbella to improve lines and folds
5. Face/neck lifting if sagging is prominent or premature, with or without platysmaplasty (muscle tightening)
6. Renuvion (J-Plasma), ThermiRF, and InMode FaceTite/AccuTite for internal tightening
7. Ultherapy and Thermage for external tightening
8. Regular Venus Legacy, Exilis Ultra, or InMode Forma treatments with facials to maintain tightness
9. PDO NovaThreads or Silhouette InstaLift cone threads for lifting and long-term collagen production

See an expert for a formal evaluation and to develop a personalized treatment plan based on your individual situation and goals. Best, Dr. Emer"