Deposit it in a bank MM fund. Then open a TreasuryDirect.gov account and buy T-bills with at least $100k. Read this article to see how to do it. This is the safest investment possible. https://www.terrysavage.com/t-bills-beat-cds/
Buy half in 13 week bills, and the other half in 26 week bills. Set up automatic renewal at maturity; you can always change that until a week before maturity.
Leave the balance in the money market fund for liquidity.