Bengaluru property upgrade: Avoiding legal headaches?

Not proud of this but I almost got duped by a pre-launch scheme a while back. I'm currently in a 2BHK in Whitefield and thinking of upgrading to a 3BHK or even a villa, maybe in Prestige City or something from Keya Homes. I already have a home loan so I need to be super careful this time. My main concern is the legal side. How do you guys *really* check RERA registration beyond just the number? Are there specific red flags in the builder-buyer agreement I should look for, especially regarding possession delays? What are our actual legal options under RERA if a builder like, say, Prestige, pushes back the OC by months or even years? Is it just on paper or can we actually get compensation? I'm trying to avoid any nasty surprises this time. Any insights on navigating these legal waters in Bengaluru would be a huge help.