No, you don't eventually start putting on weight when you're in a deficit. It seems you havr little understanding of thermodynamics.

Anyone who goes into "starvation mode" is already very lean, with little fat left to lose. But, they don't magically gain body fat.

It didn't help, because what you said is pseudoscience.

Why don't you look at the bodybuilding community.

They get extremely lean on a simple calorie deficit.

No keto mumbo-jumbo.

I suggest you do some research