Here is how to configure Windows Time Service on Windows Server 2019 so that it acts as an NTP server for domain client computers.
Type the following commands on PowerShell
(elevated as administrator)
w32tm /config /manualpeerlist:pool.ntp.org /syncfromflags:MANUAL
You can check the time synchronization status using the following command.
w32tm /query /status
Now the Windows Server 2016 is an NTP client of pool.ntp.org and its time/clock is synced with the NTP pool servers (The server is at the same time the NTP server for other domain client systems).
If your Windows Server 2019 machine is a VM inside Hyper-V, you have to disable time sync. Go to VM settings-> Management-> Integration Services and uncheck Time Synchronization. Otherwise, Windows Server 2016 time/clock will be synced with the Host time/clock.