@Bruno77, I agree with @Digital_Dave, itās about your body and what works for you. Iām not going to tell you what to do, but Iāll tell you what I do, and maybe give you some ideas.
I actually started OMAD before I started keto, about a week before. We experimented eating one meal just to see how it would go. Surprisingly well, and I wasnāt worried after we started eating keto. So, technically Iāve been doing OMAD the whole time Iāve been eating keto. Itās kinda funny, because now itās hard for me to separate the two in my mind; where I feel like Iām not being keto if I have more than one meal.
I would occasionally fast for a day or two, but now Iām at a point where I donāt feel quite right, if I donāt have at least one meal a day.
So, I started by skipping breakfast and working all day, finally to eat in the evening. I think this worked because I had so much weight to lose, but as I got closer to my target weight, I stalled. Occasionally Iāll plan to go to lunch with my wife, and I noticed my weight was a little better the next morning, after skipping supper. Since I usually work all day I decided to start eating breakfast again.
Iāll eat about four or five eggs, and some sausage or bacon. That big of a breakfast usually gets me by if I drink plenty of liquids. If I donāt drink enough water, I start to feel hungry, but for me, I just need more hydration.
I will say I donāt shy away from eating sunflower seeds (the kind you have to shell). I eat them every night. They are relatively low carb, and keep my mouth busy, if you will, so I donāt feel like I need to be eating something else.
With that said, I will occasionally come home after work and eat again. Maybe some more eggs, or some sardines and pickles and cheese, to keep it simple. I had to resist the feeling of guilt because Iām not strictly sticking to OMAD, but I remind myself āIām eating healthier now than Iāve ever eaten in my life!ā No need to feel guilty.
Itās just all in my head. Point being, listen to your body and do what feels right.
I donāt worry about calories, I just eat until Iām full, and make sure whatever Iām eating is on the āgreen listā. shorter.one/green You might call me āeven lazier ketoā. 
Hope this might be helpful, and good luck!