Received $85,000 recently. Should we put it in an ETF such as S&P500 right now or wait?

Hi Everyone
I received around $85,000 recently as a back payment for a long term consultancy assignment I was working. Instead of spending it, I was thinking of saving it on the side for the future. Now the question – should I put the amount in an ETF right now such as S&P 500. I’m skeptical of the stock market these days considering it’s already overvalued and the risk of an impending recession but then I also get a FOMO. The second option I’ve been thinking about is putting the entire money in either bonds or t-bills for a safe return without risk.

Your advice, albeit I understand non financial, would be greatly appreciated.