I also noticed under session hosts on the hostpool, assigned users shows "-" (hyphen) even though there are assigned users on the app group. In addition, when adding an application group under the hostpool, the Applications section shows the message "The host pool wvd2-test-hostpool does not contain virtual machines." even though the host pool shows as having the 2 session hosts.
I'm wondering if this has something to do with the fact I was forced to create a certain number of the resources in US regions but can't find documentation on what if anything needs to be in the same region. I basically created everything in North Europe except objects which needed to be in the US (I set the whole thing up twice trying US East and US West with the same results).
App Group Host Pool and Workspace are in US, VMs and everything else in North Europe
We have a 2019 version of WVD up and running - it works well. The 2019 tenant shows up next to arm wvd workspace in the Remote Desktop app.
The VMs in the arm wvd hostpool are created from customised images based on the correct marketplace Win 10 enterprise multi user for virtual desktops (or whatever it's called). The VMs are successfully domain joined as part of the initial deployment (we have on prem DCs and DCs in Azure + AAD in a hybrid environment).