If you need the money in short-term (2-3 years), I would split it into 2x250K and just park them in online savings accounts which currently give about 2.25% APY

If you need the money in short-term (2-3 years), I would split it into 2x250K and just park them in online savings accounts which currently give about 2.25% APY. If you have a bit longer horizon, I would go for VTI.