(Question) Onda vs. InMode for fat reduction?

As my mother gets older, losing weight is becoming very difficult, and she is particularly worried because her double chin is especially visible. She says she is stressed because the skin around her jaw has sagged and become flabby, so I have been looking into various procedures. I understand that both Onda Lifting and InMode FX are effective for fat reduction. I would like to know which of the two is more certain to be effective, how much the pain differs, how the prices differ, and if there are any side effects. I would also like to know how many sessions are needed to see results.

(Photo source - Rizon Clinic)