Hidden charges from builders are just a scam, right?

Block E, Sector 18 — I'm finally taking the plunge after years of renting. My landlord just raised rent again, fed up of this cycle. Looking at a 2BHK with S S Homes, around ₹65L. Builders always talk about basic price, but what about the actual all-in cost? I'm worried about hidden charges that pop up later, like at possession. Should I go for construction-linked or try to stretch for a bigger down payment? What's smarter?