Legal clarity on Noida Ext projects is stressing me out

Spent the whole Sunday checking out options in Sector 150. I work in real estate but buying for myself is different, man. I'm looking at a few projects, including one from RSG Landdeveloper, but the RERA details are making me nervous. How deep do you guys go into checking a builder's legal track record? I need solid advice on verifying title clarity and RERA status beyond just the certificate. Any specific red flags for delayed OCs affecting future exit options? It's a big investment, can't afford mistakes.