Thank you again FrakeTrain, but no luck! Because I have had problems using Terminal in the past, I followed your alternative instructions for deleting the pertinent .plist file by dragging it to the trash and ensuring that it was indeed removed. Then after restarting, while I saw some changes due to finder settings, the problem with blank white icons for webloc.icns still remains. I checked the new .plist file and I see that it was updated at the exact time I restarted.
What I find so mysterious about my problem is that it was reported by so many users immediately after Catalina was initially released in October 2019, and yet after all the updates to both Catalina and Safari it remains unresolved. "Curiouser and curiouser..."
What I find so mysterious about my problem is that it was reported by so many users immediately after Catalina was initially released in October 2019, and yet after all the updates to both Catalina and Safari it remains unresolved. "Curiouser and curiouser..."