You may have to delete the Folders or Files in > Program Files > Program Files (x86) > ProgramData > Users/*/AppData/Local > Windows/System32 > Windows/Syswow64 .....
What does the error Message say??
Clearly Windows Security is not allowing the Boot - as the Media is missing the required "Trusted Installer" Signature files (Secure Boot Keys)...
Turning "Secure Boot" OFF - will solve the problem...
There is another Whole Topic in regards to this issue with PE/RE
And a Newer Version of...
You do not need MS Account if you choose the Option - Work or School
It allows you to create a Local Account - just enter bogus "work / School" information
From within the Main OS - Apply the second OS image to a new partition -
then then from Command Prompt(Admin)
BCDboot %DriveLetter%:\Windows
May have to adjust Boot-Menu Time Out using MSconfig, to see the New Boot Option
I too have Purchased a Mini-PC, and am very Happy with it... two USB2.0 Ports, two USB3.0 Port, 1 VGA Port, 2 HDMI Ports, Combo Sound Port. Mounted to the back of a small Roku TV...
https://www.amazon.com/dp/B0BC7S9R5C