@Luciano Franchi
Hi,
I suggest you use the second method.
My understanding is you can use Essentials only to virtualize another copy of Essentials, but you are not allowed to run any other VM's under Essentials.
You can refer to the following information:
From a licensing perspective, Windows Server Essentials allows you to set up the Hyper-V role and virtualize your environment. The license allows you to set up another guest operating system that is running Windows Server Essentials.
https://learn.microsoft.com/en-us/windows-server-essentials/install/install-and-configure-windows-server-essentials-or-windows-server-essentials-experience#BKMK_VirtualWSE
So you'd better migrate from Essentials to Standard, purchase Windows Server 2019 Standard license and CALs.
Then use the DISM method to insert the Standard key
https://learn.microsoft.com/en-us/windows-server-essentials/migrate/transition-from-windows-server-2012-essentials-to-windows-server-2012-standard
Hope above information can help you.
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