Rolling over 401k to IRA - large balance and anxiety about timing

I have close to 6 figs in my employer 401k, recently left company after being employed there my entire career. New company doesn’t have many investment options so looking to roll to externally managed IRA however terrified about how timing could affect me. I know I can’t time the market and no one knows when is best, etc. Just trying to determine how much could be at risk by being out of the market for a few days. Obviously, there could be an upside as well.