I am not surprised; the download does say that it is only for 64-Bit Windows 10. I am sure they haven't tested it on Windows Server 2019. I will pass this report along; we'll see if they can come up with a fix...
Knowing it was not supported, I tried anyway.
Got it working with the latest drivers, but it would drop out after roughly 5 minutes.
Tried the firmware update, hoping for an improvement, but not successful.
Thinking of trying to boot Win10, perform the update, then return to server 2019. Since it's firmware, may work?
46.00 is the latest version, but yes the upgrade process can be somewhat tricky: