Hi there,
By default, Windows security settings allow remote RDP logins through Remote Desktop Services (TermService) when:
-The user account is a member of the local group Remote Desktop Users or Administrators;
-The user group is allowed to connect in the Local Group Policy parameter Allow the log on through Remote Desktop Services.
It seems you have done most of the troubleshooting steps to sort this issue out. Try to turn off Hyper-V enhanced session mode and check the result.
The below thread discusses the same issue and you can try out some troubleshooting steps from this and see if that helps you to sort the Issue.
I am getting "To sign in remotely, you need the right to sign in through Remote Desktop Services. https://social.technet.microsoft.com/Forums/office/en-US/08bc21df-59f0-40b0-ad57-ad633ff5e5e0/i-am-getting-quotto-sign-in-remotely-you-need-the-right-to-sign-in-through-remote-desktop?forum=ws2016
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