Cross your fingers. Just put on the latest (preview) fix for Windows 10 version 2004 today. Doesn't explicitly list a fix, but my machine has survived a couple of restarts without prompting for a password. Since others though they had fixes that eventually turned out not to work, I'll update in few days on whether it is still working or not.
see https://support.microsoft.com/en-us/help/4571744/windows-10-update-kb4571744
If you feel like trying it, do settings, Windows updates, Optional fixes. Normally I would not recommend applying these optional fixes as sometimes the are bad or even old and superseded. So Only apply for now if you really are willing to put up with possible new problems.
Updating 9/5/2020 to say that although the fix seems to increased the time between getting prompted, (managed 24 hours) it still hasn't completely fixed the problem.