Safest NIFTY 50 Stocks

Hey guys, I’m new to the stock market and planning to invest ₹10 lakh for around 3 years I know NIFTY 50 stocks are generally considered safe, but after seeing cases like Adani stocks crashing post-Hindenburg, I wanted to ask **Which NIFTY 50 stocks would you say are the safest to hold for 3 years, and why?** Also, If I open a demat account with Upstox or Zerodha, can I safely hold stocks worth ₹10 lakh there for 10 or 20 years? From what I understand, even if the broker goes bankrupt, my Demat account will still be accessible through government website. Is that true? And is there anything else I should be aware of as a beginner? Sorry if this sounds noobish—just trying to understand things better. Would appreciate any insights!