How long till ketosis kicks in?

Been doing 16:8 for a while. My goal is to lose 20-25 lbs. And lower my insulin, heal my metabolism. I’m 49 male 5’8” started at 200 lbs. I’m currently 197.5lbs. My issue is not feeling like I’m actually getting into ketosis with 16:8. I’m liking the sounds of ADF as it gives more time to actually start burning fat. I’m a chef and learned a few years ago that I was at risk of metabolic syndrome mostly due to snacking at work. It’s been liberating learning to not eat all the time, but losing weight is proving challenging.