New Delhi property negotiation is mostly a facade

Loan pre-approved, budget set for a 3BHK in Jhilmil Colony, around ₹2.2 Cr. I'm looking at a Vishal Developers project there. Honestly, negotiation seems tough for New Delhi properties. Kitna realistically knock off kar sakte hain on the listed price? Is 5% bhi possible ya just wishful thinking? Also, construction-linked payment plans better hain ya lump sum down payment? Builder bol raha CLPs are safer but I'm not sure about the leverage. And these PLC and floor-rise charges, are they actually worth paying extra for? Ya bas builder ka tareeka hai to inflate total cost? My parents keep saying to push for a spot discount, but builder mana kar raha. Any experiences with Vishal Developers?