I would ease into OMAD if that’s the route you ultimately want to take. I would suggest starting with 16:8, then move to 20:4, then- if you feel you want to- move to OMAD.
My SW was close to yours (329 lbs), and in about 6 months of mostly 16:8 + \~2mi nightly walks through the neighborhood, I’m down to 282 lbs (as of this morning).
Sorry to burst your bubble on the eating every 12hr routine but it may not be enough to get your insulin levels down enough to access your energy stores. Possible for some people but it may help if your time between meals is a bit longer. I started with 16hr fasts and I didn’t lose any weight. I pushed it to 20hrs and that seems to help…but I’m 15lbs away from goal so it’s harder to lose the last few pounds. Since you’re new to fasting, start out easy. Do a true 12hr fast and a 12hr eating window. Focus primarily on eating less processed foods and even lower carb (makes fasting easier). A week later try 14/10, then 16/8 until you find a good fit for your goals and lifestyle