Family upgrade: RTM vs UC for peace of mind

Been looking for a 3BHK in Sohna for over a year now, especially around Sector 32-33. My wife's really pushing for ready-to-move because of kids' school admission next year. She wants no delays, you know? Bestech projects look good. Under-construction flats are cheaper, but RERA horror stories are real. Is the RTM premium worth it for peace of mind? Not sure if stretching our budget is better than risking a delay. Anyone bought UC recently in Sohna and regretted it?