@HoldMe - If nothing can be done at present due to a design change being unconditionally forced on us (as is the case with the gray call screen), then I have also found it is acceptable to suggest a positive change, such as Apple adding a toggle switch in Settings users can turn on to have Dark Mode applied to the Call Screen as it once was, or have a default image applied to the call screen for numbers not in your contacts, or contacts without, “posters” as they are called. I think the action you proposed in your deleted post is good to do, as it definitely gets word to Apple about the difficulty you are having with the gray call screen, but the officially approved method of providing feedback to Apple is through their feedback page here: Feedback - iPhone - Apple
While it is said Apple personnel never read posts on this forum, I do believe expressing your opinions here in a positive way can create solidarity with other users sharing your concerns, and they can in turn be stirred to provide feedback to Apple through approved channels. Let’s hope Apple makes this right for all of their users soon by simply giving us a choice in Settings.
[Edited by Moderator]