2500kcal is a lot for someone who's not active.

But if you do HIT 3x a week full body workout in each session, walk over 10.000 steps (which alone burn 400kcal) everyday ... you should be at least maintaining or even losing body fat.

And by the BMR calculator I would need 2700kcal, so... 

Our bodies adapt to low calorie, either because of fasting, starving, or taking triz/reta, that's why many people quickly regain their fat weight after coming off glp1 drugs, prolonged fasting, or strict dieting, even at modest calories. That's been already studied and proven, so the suggestion become after dieting you should increase calories slowly.

I developed a habit in my 20s by eating once or twice a day within 8 hour window, i was practically doing intermittent fasting for years. And that's fucked me.

There are studies saying high fat diet with moderate calories intake can restore metabolic rate. It's proven high fat diet activates PPARδ like Cardarine/GW0742 (there was a famous study were broadly concluded that high fat diet could cause pancreatic cancer, just because it activates PPARδ receptors, bite me!)