I did keto, and it worked quickly even after a year of no period 2 weeks of keto it kicked started it - but once i stopped the pcos got bad again. -

I have been doing low carb for 2 months, no extra workouts and lost 25 lbs. I eat less than 50 carbs daily. It might be worth looking at.

I've been doing the keto diet for 2 months now and I've lost 27 pounds so far

For weight loss you need to be in a calorie deficit, no matter what diet you're on. That being said, some types of food will make you feel better than others but it's all down to you. A paleo/Mediterranean diet is the best catch-all diet that the highest number of people would benefit from, lots of vegetables and lean protein with healthy fats like olive oil.
Personally, I prefer a plant based Mediterranean diet with a little fish. I eat roughly 1800 calories a day and aim to burn 2500-3000 every day.
Low carb is great if you plan on cutting out things like bread, pastries, biscuits etc, but you'll need to make sure you're replacing them with complex carbs and fibre from vegetables.

I read somewhere to calculate the amount of calories you should approx be on you get your goal weight (GWx12). For example my goal weight is 110lbs. So 110x12=1200 calories. This method can also be used to calculate best amount of protein to eat. But instead you simply get your GW (110) and x1. So 110x1=110g of protein. Whilst im still attempting to adjust to such high protein i think it sounds like the best thing to do for me at least as protein is sooo filling and satiating.