Morpheus 8, Ultherapy or other treatment for skin tightening?

Hello. I'm interested in tightening the skin on my abs / obliques (to give me shape again), underbutt", arms / sleavage. I was wondering which laser would be best. I am also wondering if peptides like cjc 1295 or other would help. I am 45. Workout 5-6 times a week with weights and cardio, but feel that you can't tell anymore due to skin laxity. Thank you.