Medchal project mein hidden kharche: any tips?

Been visiting sites for a few months now, especially around Medchal. Salarpuria Sattva ka project dekha, show flat toh mast hai. But honestly, I'm scared about the hidden costs beyond the property price. Stamp duty, registration ke alawa aur kya kya kharcha lagta hai? And site visit pe kya kya puchna chahiye jo builder nahi batayega? Under-construction project mein delivery risk kaise check karte hain? Bahut confused hoon.