according to VMware Knowledge Base there is no vCenter (for Windows) version available that is supported on windows Server 2019.
Upcoming versions will no longer be available for Windows. For more information see Farewell, vCenter Server for Windows - VMware vSphere Blog
I am not quite sure what you mean, but if you mean that when you can select the OS as a GuestOS identifier, it's not yet available. See this KB https://kb.vmware.com/s/article/59222?lang=en_US