Retiring in 4 years: how would you diversify a highly concentrated US portfolio?

Hello folks, I’d like to hear general views on long-term portfolio construction for someone approaching retirement in about 4 years. Quick background: Current net worth: around €700k Current allocation: roughly 95% US large-cap equities, 5% crypto I keep investing monthly, around €7k per month I do not plan to sell my current holdings I am only using new contributions to gradually diversify What I’m trying to understand: How do people think about reducing concentration risk in a portfolio that i