Disconnect all your devices from internet and get rid of your internet connection, then u can't gamble anymore

not exactly, there's always the possibility of falling back on real life casinos.
Maybe work on your physical health. Start exercising/working out with some goal to reach like losing xx amount of weight. Or maybe walking/running/biking/swimming with a goal to be able to reach XX mi/km or whatever. Or train to be able to compete in some amateur walking/running/biking/swimming event. Or take up an organized team sport to help give you more structure to help keep you at it.
imo, if a person doesnt have the mental capacity to stop themselves from gambling, they definitely lack the mental capacity to dedicate themselves to regular exercise.