Is getting possession without an OC really that risky in Bengaluru?

Kanakapura Road keeps coming up, especially for smaller 2BHKs now that the kids have moved out. We're downsizing from our big house, looking for something manageable with an elevator. I'm seeing a lot of projects, like Avenew Projects' Manya Magnaville, but I'm really worried about the legal side. How do you actually check RERA registration properly? I mean, beyond just seeing a number. Are there specific red flags to look for on the RERA site itself? And what about the Occupancy Certificate (OC)? I hear stories of builders delaying for years. Can you even get possession without it? What real problems does that cause later? My friend had issues with property tax because of a delayed OC. Has anyone faced this in Bengaluru? Is RERA actually effective if a builder tries to push possession without a proper OC?