A good suggestion I have heard is that a portfolio is a living document and will change.
I have two portfolios. Those for commercial purposes, where the “standard” photos that everyone likes are added and some of my own personalised style photos. The other portfolio is more the artist portfolio containing photos that present the photos more unique and closer to personal style.
My process selecting is dependent on the audience. So I put myself in their shoes and try to figure out what they will like. But never forget your ‘style’ must be prominent through all the photos.