It's horrible, I have this same problem. Everything I used to do to maintain my weight just no longer works. I could eat 1,000 calories a day only and STILL not lose weight. I'm a surfer and so I exercise a lot, that's never been the problem. and I eat most meals cooked at home, very healthy.
Our metabolisms change when we enter menopause, and I do not think there is much study on this at all. It's not as simple as calories in, calories out. Something else is going on.
I tried Keto (which used to work so well) and found it incredibly hard to get myself into ketosis, where previously it would be easy. I managed to enter ketosis and still no weight loss. I tried intermittent fasting, which turned me into a grumpy horrible person, and still no weight loss. I tried calorie counting, still no loss and constant hunger.
The only dietary change that worked was Dr Hyman's Blood Sugar Diet. You have to eliminate all the following: bread, potatoes, rice, pasta, beans, corn, sugar, dairy, coffee, and alcohol. It's incredibly limiting, but I wasn't hungry. Over about 3 months I'd lose about 1.5 kgs. But the restrictions especially no coffee means it's completely unsustainable.
I've suffered from high blood sugar for a long time and have to work hard to keep it down to avoid diabetes. So eventually I tried Mounjaro. It's a total game changer. My blood sugar is under control and I'm very slowly losing weight, I've lost 7.6 kgs in 7 months. I still have excess belly fat, but overall it's getting better.
Menopause changes so much in our bodies.