10 years of renting, finally pulling the trigger

Since last Diwali, I've been so fed up of renting. Landlord ne rent badha diya phir se. Finally, I'm serious about buying in Hyderabad. Looking at a 3BHK, maybe Salarpuria Sattva. But yaar, yeh super area vs carpet area ka chakkar samajh nahi aa raha. Builders kaise inflate karte hain numbers? Is construction-linked payment plan better for a ₹1.5 Cr budget? Resale mein negotiation zyada hoti hai kya?