If it's not on the website, I'd assume that it's not yet supported, but you might want to contact Tableau Support to confirm. If not yet supported, perhaps they'd be able to give you a target timeline.
Thanks what I thought too.
Thanks for the reply.
When you hear back from them, let us know what you find out!
This is what I got back from Tableau Support:
Thank you for contacting Tableau Technical Support!
Our specification does not explicitly call out any Windows operating system. Instead the specification states we support Windows operating systems 2008 R2 and newer which should include Windows 2019.
And after researching internally, we have not had any reports of Tableau Server not working on Windows Server 2019. So if there is an install problem or whatever, we would be glad to investigate.
Great. Good to know!
Thanks for the feedback.
I got similar feedback from support. They had mentioned that they generally add the newest version of windows to the website around September of the following year.