Overweight since childhood and nothing seems to change

When I was a toddler I was a completely healthy weight, around 2nd grade is when I became overweight and ever since then I have not been able to change it at all. I have no overweight family members, my mother is a normal weight, my father and all my extended family are too. but for me I’ve forever been overweight.

By the time I reached the age of 12 I was incredibly fat, nobody in my family ever commented about it but I was able to notice the difference between me and my friends. I wasn’t bullied or abused, I never used food as a coping mechanism. it was just the ungodly and unmovable weight, I hit puberty at age 11 but even before that I was fat and my weight never distributed in my teens.

By age 15 I began experimenting with diets and caloric deficits, I lost 10lbs at 15 and went from 180 to 170 (I’m a 5’2 female) but it never went below that, and when I gave up the deficit and followed a maintenance diet recommended by a professional, I immediately gained it back. then the year after that I lost 30lbs through a lower caloric deficit and more exercise, I decided I was happy with that weight and once again, at the start of a maintenance diet I gained it all back.

Then at 18 I began another caloric deficit which was also recommended by a doctor, but absolutely NO weight was lost, none! not a single lb, I made sure to follow the exact plan and never overate. but it seems like this weight is simply here to stay. I’m 20 years old now, still at the exact same weight I’ve had for over a decade. I’m not sure what to do because nothing has ever helped. I don’t live in the US so it’s not about over-processed food. I rarely eat fast food because it’s just not in my culture, we all eat the same cooking my mother prepares.