Upgrading in Gurugram: RERA fears

Visited Suncity Vatsal Valley Independent Floors 1 last weekend. We need a 3BHK for the kids, and my wife's main priority is a safe place with proper documentation. I'm getting confused with RERA compliance checks. Some projects, even by known builders like SS Group, seem to have partial RERA registrations or delayed OCs. Is it common to get possession without OC in Gurugram? How do you verify a builder's legal track record, especially when they have multiple projects? Not sure if I'm overthinking this, but it's a huge investment.