OMAD is an extreme version of intermittent fasting. i have been intermittent fasting every day for about 4 months now. vs OMAD, intermittent fasting has an "eating window". the most popular seems to be 8/16, eight hours of eating followed by 16 hours of fasting every 24 hours. when i started, i went to 8/16 for the first 3-4 days, starting my eating window at ~10am and ending at 6pm. but within a week or two i gradually moved my stop time back to now where most days my eating window is only ~4 hours.
anything over 12-14 hours of fasting will get you on an effective eating schedule, so why not try to move more slowly toward your OMAD goal. a good start is merely to stop eating after dinner, say 6-7pm, then have no food (got that? .... NO FOOD) until ~9 or 10am the next morning.
i still miss eating at night some days. i'm a pretty good cook and i often have some leftovers from the day for a meal tomorrow, so cheating is a simple 1-2 minutes in the microwave. but then i think about how good i'll feel tomorrow, have a cup of black coffee and the feeling doesn't usually hang around long. i must be getting better, too.... a few days ago i baked some shortbread and there are a zillion very tasty calories in my kitchen right now. hard even for me to believe, but at the moment i have zero motivation to raid that stash.
this next point will be hard not to take the wrong way, but what you do eat seems to be horrible. corned beef? sausage? stop eating processed meats. learn to steam vegetables. what sort of grocery stores do you have locally. at mine even if i was lazy, i could still eat well as their deli dept has roast chicken and there is a salad bar (but limit your dressing to oil/ vinegar, no ranch/ 1000 island, etc.... even the good sounding ones are often loaded with sugar).
i've had to fight back a weight gain twice in my life now. the first time in my 40's was because i was convinced that i didn't want to turn into what some of my friends looked like. now i am 65 and this time it is because i want to live longer. i have already had two friends die because they ignored their health. last year i drove up to Wyoming to see the total eclipse... my first. already planning on seeing my 2nd in 2024. i'm feeling good about making that now.