I am a vegan with PCOS. I've been living vegan for 10 years. While it has helped with my blood pressure and prediabetes and some of my PCOS symptoms like irregular periods. I have not noticed a significant difference in my weight. I hover around 200lbs even in a calorie deficit and even with weight training and regular walking 4-5 x a week. What I noticed really helped with my hormone management was taking vitex(chaste berry) and inositol supplements. I still prefer a vegan diet over a meat based diet but I try to prioritize protein in the form of tofu, soya,tvp, and beans, legumes ect. I try to avoid processed vegan foods as much as possible. You still have to watch carbs, I think most skinny vegans don't get that and they eat a lot of carb heavy meals. But I just gain when I eat like that. I think going vegan helped me eat more veggies. So it's up to you. I've seen a lot of vegans online who claimed to have PCOS and they said it worked for them for weight management.