The most straightforward way to address your chin, and give you the best cosmetic result, would be with a chin implant. Chin implants come in all shapes and forms. Therefore, seeing you in person a=or via multiple photos (side, profile, and front on) would help determine the best shape of an implant to use. Recovery is usually about a week.
Chin implant candidate for weak chin profile
Chin implants and the mandible are both 3-dimensional structures, so a full set of facial photographs are required to make a determination about what may be needed. Chin implants are manufactured in a large variety of sizes and shapes, which is best determined at time of the consultation and examination. Chin implants are composed of Silastic, and are usually placed through a small incision underneath the chin under local anesthesia as an outpatient surgical procedure. For more information and many examples, please see the link and the video below
yes, the sliding genioplasty is likely the most natural option. A chin implant could work but you have to avoid excessive width to the chin area since you appear to have a more narrow lower jaw. Otherwise the chin looks too strong and isolated. Costs vary. Consult a Maxillofacial surgeon
What you are demonstrating is a widening of the chin on the sides. This can be done with an implant that is made to specifically have that effect. It can or can not produce increased horizontal projection based on your desires.