Have a look for the 5+ stone to lose thread on here, as advice from people who've never been seriously overweight might be well meant but is unlikely to actually help.
I lost 49 kg (which is around 7.5 stone very roughly) during the pandemic, kept it off for a year but have put 18kg (just under 3stone I think) back on - I know why and am now back on the case. Jason Fung's 'The Obesity Code ' and 'Life in the Fasting Lane' and Gin Stevens 'Fast Feast Repeat ' and her free podcasts helped me get my head in gear and stay that way. I've just re-read The Obesity Code and am about to re-read the other books and also read 'Why we eat too much ' which I haven't read yet.
Chronic obesity is hormonal (Insulin and Cortisol primarily, I don't mean estrogen and progesterone so much). If you've been obese for years and it's only getting worse you're probably insulin resistant. Genetics play a role so it's not surprising many of your family are similar but you CAN reverse it.
Intermittent fasting and cutting right down on processed and added sugar (without worrying about naturally occurring sugar) and cutting down on processed grains (flour basically - bread, cake etc) is what worked for me. I ate whatever I wanted within a 4-6 hour eating window in every 24 hours as long as I avoided processed sugar and flour products except on special occasions (although sometimes I counted my children having baked as a special occasion I didn't include random work acquaintances bringing in birthday cake! So most weeks I stuck to it 100% and if my own family had birthdays I gave myself leeway on what I ate but never extended my eating window beyond 6 hours maximum).
Once I started maintaining I initially just extended my window to 6-8 hours and it was fine, but then a year in I hit another stressful phase of life and slipped into longer windows and then fatally the compensatory eating of products containing processed sugar and flour 😳 For me it's almost like an alcoholic slipping back into old destructive reliance on alcohol after being "dry" for a couple of years.
However I haven't put even half the total weight back on and I'm back on the case of getting back into good habits now for the sake of my health. So I do count myself as a success story 😳😊🤣
I also upped my activity very significantly mainly by walking, and went from struggling to walk up the hill near my house to walking 5-7km every day (which I've kept up) and hiking in the alps for fun (which the above mentioned stressful phase has meant I haven't had time for recently) but firmly believe this isn't the main thing for weight loss on the scale (although it helps to reduce insulin resistance indirectly by building skeletal muscle and the change it makes to body shape is motivating).
Stress and sleep deprivation are linked to weight gain for me both psychologically due to the self destructive coping mechanism I've maladaptively formed a habit of falling into, and due to Cortisol - it's a vicious spiral I have to consciously break and stay away from.
Health is my motivation and appearances are a wonderful side benefit!
You CAN do it but it's not just about willpower. Have a read of Jason Fung to understand why all diets work in the short term but "eat less and move more" doesn't cut it long term because of insulin resistance and the body's tendancy towards homeostasis.
Good luck!