My first home purchase in Sector 122 – total cost confusion

Budget finalised, loan pre-approved – ab Sector 122 mein flat dekh raha hoon. Royal Next Homes type projects mein interest hai. Builder quotes toh bas base price dete hain, but all-in cost ka kya scene hai? Matlab, stamp duty, registration, PLC, parking, yeh sab milake kitna extra pakad ke chalun? Suna hai possession ke time pe bhi hidden charges aate hain. Koi bata sakta hai ki yeh total cost kitni badh jaati hai? Doesn't want any surprises later. Any hacks for these extra costs?