@christianmontoya Here's what I have for role assignments. The second one (the service principal) was never used because the host pool creation on the marketplace would always fail with the same "User is not authorized to query the management service" error. So I ended up creating the host pool with my UPN instead.
@DavidMagrathSmith : Did you get any further on this? Primarily, it's a little challenging to troubleshoot permissions/access without specific details. If you have official support through Azure, I'd recommend going that way and they might be able to get down to the root cause. Just a notice though: even if you have a Global Admin account, that does not automatically give you access to manage WVD.