New Delhi flat search: Legal traps se kaise bachein?

My kids' school admission is next year, so we desperately need a bigger 3BHK. Looking at Vasant Kunj ya Dwarka, but builder ka track record checking mein confused hoon. Angels Real Estate jaise builders ka legal history kaise verify karein? Suna hai RERA complaints ka process bahut slow hai, kya woh actually effective hai? Aur builder-buyer agreement mein kaun se clauses pe dhyaan dena chahiye? Koi red flags batao jo sirf builder ko favour karte hain. Family ki safety aur future ka sawaal hai, don't want any legal issues down the line, especially with all the DDA Meera Apartment delays we hear about.