How many meals a day is most effective when dieting?

I'm on a diet

We are also following a diet plan this time.

Last year, I lost a lot of weight by eating only one meal a day.

It's difficult in the long run

I'm going to try increasing the frequency a little.

Would it be better to eat three small meals a day?

Or would it be better to have two meals with a time gap between them, like intermittent fasting?

If there is a method that has a double effect, I would like to hear a real review.

I'm exercising as well, but I'm not losing weight well, so I keep getting exhausted.