Keep RSU or diversify ?

Net worth: ~$6M

About 70%+ is concentrated in two FAANG stocks from vested RSUs accumulated over many years. The stocks have performed extremely well, which is why the position became so large.

If you were in my shoes today, would you continue holding, or would you diversify some portion into S&P 500 index funds?

My main objective is reducing concentration risk and preserving wealth rather than maximizing returns.

I have stopped working, so no new RSUs coming in.

How would you approach this, and why?