change time grayed out in windows server 2016
Solution 1:
I had the same problem and the issue wasn't related to policy. Only changing it in the Local Server section of the Server Manager worked. See this article: https://www.dtonias.com/set-time-date-timezone-settings-server-2016/
Solution 2:
"Some settings are hidden or managed by your organisation" clearly indicates that settings locked down by some policy (local or domain). Try to use Resultant Set of Policy (rsop.msc) or gpresult command line tool to see which exact policy blocks these settings.