Thank you! I needed that help. It works now.
NOTE: I did not know how to do this. I just clicked on “update theme” in WordPress, and my CHILD theme disappeared. I could not customize because WP told me the directory no longer exists. I reinstalled the CHILD theme from my previous download. [I RESTORED my backup WP files.] Now Chrome browser shows the header text color the same as the custom link color. I chose BLACK header text color again, and now Edge and Chrome (incognito) do show me the black header text, but regular Chrome browser remembers who I am and shows me the BLUE (link color) header text. Of course I will live with this, so long as my customers see the black text.
Maybe there is a better way that I should have updated the theme.