400k inheritance, should i invest now?

Hey everyone, I recently received an inheritance of about $400,000 and I’m trying to figure out the best way to invest it for the long term. My initial thought was to put most or all of it into broad-market ETFs, such as an S&P 500 index fund, since I don’t need the money right away and my goal is long-term growth. What I’m struggling with is the timing. Part of me thinks I should just invest the entire amount immediately and let time in the market do its thing. On the other hand, investing such a large lump sum all at once feels intimidating, especially with all the uncertainty in the markets right now. I’ve seen people talking about a potential crash due to SpaceX. Would you invest the full amount right away or wait a month for the market to stabilize?