Noida investors: Payment plans and hidden costs?

Sector 89 — researching this area for a while. Fed up of renting, landlord raised rent again, so I'm finally taking the plunge for a 3BHK. Budget around ₹1.5 Cr, trying to maximize ROI. Many construction-linked payment plans. Is this always smarter than a down payment scheme for an investor? Feels like they lock you in. Super area vs carpet area is confusing. Builders like ATS or Godrej show huge super areas, but usable space feels way less. How do you factor that in? It's a hidden cost. Should I stick to clear carpet area pricing? Are brokers truly useful or just pushing inventory? Not sure if I'm getting the best deal. Any tips on payment plan leverage or avoiding the super-area trap, especially near the Aqua Line extension?