Hidden red flags in RERA registration most buyers miss?

₹2.5 lakh extra every year for rent. Finally taking the plunge for a 3BHK near Dwarka Expressway. Pioneer Araya dekh raha hoon, par Sahara India Pariwar Builders ke track record pe doubt hai. RERA registration check crucial hai. Sirf website pe naam enough nahi, hidden red flags kya hain? Agar builder delay karta hai, toh RERA options kya hain? Compensation milti hai ya bas paperwork? Builder ka legal background kaise verify karein? Don't want to get stuck. Tips for first-timers?