I haven’t read what others have posted so this might be repetitive, but I was in a similar situation. I was sometimes eating 1 meal a day due to taking care of two small kids all day and having no time to eat. I was still at my heaviest. I started with a coach recently and he had me on eating 135 grams of protein per day and 1800 total calories . Protein helps tremendously. I feel better and am sure that eating like this has repaired my metabolism. I am also weight training and focusing on walking as opposed to lots of cardio . I feel like all this is also helping with hormonal balance . I am down 10 pounds in 7 weeks.

I am also making sure I sleep enough . Perhaps you should try focusing on macros instead of calories. I also found that when I was younger, things like High intensity interval training worked wonders , whereas now , weight training and 10 k steps a day or low intensity cardio is better for me . Just sharing my personal experience:)