Is TLS 1.3 supported on windows server 2019?
I found a documentation from microsoft but for some reason the matrix doesn't include server 2019: https://docs.microsoft.com/en-us/windows/win32/secauthn/protocols-in-tls-ssl–schannel-ssp-
Windows Server 2019 – TLS 1.3 Support
Securitysslwindows-server-2019
Best Answer
Windows Server 2019 is little more than a rebranded Windows Server 2016 which is most likely why it's not mentioned in the compatibility matrix you mention.
If you need to compare, Windows Server 2019 matches Windows 10 1809 (just like 2016 matches 1607) so you can take that for reference.
Feel free to edit the Microsoft documentation to add Windows Server 2019, if the edit is approved that'll actually give you an "authoritative" answer from Microsoft.