1. Let the money sit in your bank account (wallet) for at least one month. It will allow you to settle down your heightened emotions. Just let the amount sit and do not do anything with it for at least one month.
That's if the winner doesn't already have a plan for the win. If they do, I don't think there should be anything delaying them further than to plunge into what their dream is and make it come alive.
2. Go on a low-cost, week-long vacation with your family and friends (do not tell anybody about your winnings; do not boast) immediately. It will help you make your relationships stronger and will certainly help in doing step 1.
3. Do not change your lifestyle immediately, as it will help you to remain disciplined, which will eventually help you out to earn even more.
Those are true. It's needless announcing oneself too soon after a major breakthrough. You never can know who isn't happy with your success.
4. Consult a certified financial consultant and invest in a diversified portfolio other than gambling, probably for the long term, at least 80% of your winnings.
That's apt and sound reasoning. Take cash out online and put in offline venture(s). It's a better way of safeguarding one's source of living. If the lucky winner is a crypto or forex trader, it will be ideal to also invest there.