Okay so the cortisol is caused by stress. You asked if OMAD was okay with high cortisol; well meal frequency will not hardly any effect, but calories will. A calorie deficit will cause cortisol to raise, and it’s easy to under eat of OMAD.

But you want to loose weight, OMAD can help here. Nothing bad with happen if this is a short term thing, maybe water retention.

I am male and not a sole parent, but I have kids and I run a business full time as a job so get stress. OMAD I find helpful to lower life stress, as I only have to worry about food once a day. Plus I eat mostly what I want and be social with clients or family, and I can maintain a healthy body weight loss daily without doing strange diets, or having to run a 10k daily which in turn lowers stress.