If I got a $350K windfall right now I'd probably put about 70% of it into tbills (6 month to 1 year paying ~5.5% right now) and another 20% into 2 to 5 year tre

If I got a $350K windfall right now I'd probably put about 70% of it into tbills (6 month to 1 year paying ~5.5% right now) and another 20% into 2 to 5 year treasury notes (paying ~4.7% right now) with the remainder going into an S&P 500 ETF like VOO. I'd DCA into stocks & etfs as the tbills matured. You're right, these 5% rates probably won't last long (though some pundits are saying we're going to be seeing 6+% due to high demand and stubborn inflation so who knows...) but a 5.5% yield on ultra safe treasuries is too hard to pass up right now plus there's no state tax on that interest.