If easing into it doesn’t work for you, just jump in. Eat a huge meal (like really big) and start your 23-24 hour fast. Just do it. You can worry about making your meal normal sized later on after you get back on the OMAD schedule.
I like a smoothie with protein powder in the morning and then OMAD. It’s like a baby meal. Then if I need more after my big meal, I sneak in some nuts for protein and that usually works. I find it hardest when I trigger my addictions to carbs and stuff, so like having a big breakfast leaves me wanting more food later.
Good luck. I’ve never made it all the way to OMAD and I live somewhere between 5’s and 6’s. You really have to try and not eat in the middle. It’s got to be 2MAD, one big and one little meal. OMAD people love not calorie counting, but here, you have to, so maybe ease yourself back out with an 400 calorie beginning to your six and then your OMAD, minus 400 calories.