Hidden costs buyers only discover after possession

I'll be honest, I'm fed up with builder hidden costs. Looking at Goyal Luxury Floors for a 3BHK upgrade from my 2BHK. Brochure achha lagta hai, but kya surprise charges post-possession aate hain? Rahul Mangla ke projects mein hidden maintenance fees ya unexpected costs kitne hote hain? Is ₹2.65 Cr truly the *final* total-cost?