My Gurugram 3BHK dream: Scared of legal traps

Okay, I'll be honest — I'm completely overwhelmed by the legal side of upgrading. Currently in a 2BHK near Sector 65, I'm eyeing a 3BHK. How do you actually verify a builder's legal track record and RERA compliance for projects like BPTP ones? What are our real legal options if a builder delays possession, beyond just basic RERA complaints?