OMAD can work since it’s quite hard to consume a caloric surplus in only one meal, especially if your tall. However, personally I made a couple mistakes and managed to gain some kgs. So the following things you should definitely avoid if you don’t want repeat my mistakes.
Sodas and sugary drinks contain calories and you have to account for them. You might have a coke with your meal but you should definitely avoid it during fasting periods.
Ordering out fast food all the time. It’s okey to get some pizza from time to time, however ordering huge amounts of fast food (like a whole family sized pepperoni pizza with extra cheese and binge that until you get sick.. yeah I did that a couple times) while thinking it’s fine because you only eat once a day won’t work. OMAD ain’t magic, you still need to be in a caloric deficit.
I‘m a software dev working mostly from home and sometimes I don’t even get out of my bed so I’m literally as sedentary as it gets. However, this lifestyle lead to significant muscle loss. So get your self at least a 30min walk a day or even better a gym membership or a place to do some calisthenics, otherwise you won’t be happy with your physique even after the weight loss.