I have a Dell XPS laptop running WIN 10 pro (1909) and have had this issue as long as I have had the computer. I go and change/re-apply all the settings for the screensaver and lock screen, and things work for a day or two, and then eventually stop working again. Specifically I always have the "on resume display logon screen" box checked.
Typically, I reset these and re-apply the settings, and things work for a bit, but then stop working after a few days.