It’s bleeding obvious, of course, but you just have to find what suits you, your temperament and lifestyle. For me, the 5:2 is it. I’ve been doing it since it hit the headlines years ago (I’m not even sure how many!) and it’s just normal life to me now. I love my food and drink, and eat heartily five days a week, no miserable calorie or carb or point counting, no small plates, no guilt, no denying myself. On the other two I eat one healthy meal only, though some split the calories over two or three very small meals. I don’t find it at all arduous and it’s really made me appreciate my food more. I lost a stone easily in the first weeks, but am now just maintaining my present weight, which I’m happy with - if I wanted to go lower I’d simply add a third fast day for a while. The 5:2 has added health benefits too - my blood pressure and cholesterol level dropped significantly after a few months, and have stayed down.
Exercise is crucial though, if you can do it. There are so many workouts on YouTube these days, suitable for most abilities. Michael Mosley, the 5:2 man, has easy options there too. He advises two brisk daily walks of just ten minutes - again there are online power walking videos if you want to do them indoors - and exercise snacking, which takes just a few minutes.
I hope you find what works for you!