I’d do the same. Quietly pay off everything I owe, stay in my current house, set my kids up with $10 mil funds, put a large chunk ($50-100 mil) in high-yield savings, and donate the remainder. If family was struggling financially, I’d help as needed, without ever revealing how much I really had.
Money makes people act like monsters. I only need enough to live, enjoy myself, and keep stress low. Wanting more for the sake of more has never interested me.
RE: What would you do if you had $500,000,000?