Karl-WE that's not true any longer and I'm testing HF4, have a look at the Teams VDI documentation:
Installation instructions for Windows Server 2019
For Windows Server 2019, the only supported installation method is:
Dism /Online /Add-ProvisionedAppxPackage /PackagePath:<MSIX package path> /SkipLicense
Make sure sideloading is enabled, and that WebView2 is installed. See 'Requirements' section above.
The /SkipLicense command is needed because the MSIX package isn't considered a "Store Package" (since it wasn't downloaded from the store). Therefore, for the Dism installation command to succeed, you need to enable this policy as well during installation time: Computer Configuration > Administrative Templates > Windows Components > App Package Deployment > Allow all trusted apps to install.
Known limitations:
- Classic Teams on Windows Server 2019 isn't displaying the app switcher toggle if Classic Teams version is lower than 1.6.00.33567
- New Teams on Windows Server 2019 currently isn't compatible with FSLogix and fails to launch. See https://learn.microsoft.com/en-us/fslogix/troubleshooting-known-issues for more details.
- New Teams MSIX installer isn't registering UC Typelib, causing Outlook presence bubbles to show as grey/unknown even if the virtual machine does have the Classic Teams client installed as well.