Delta 3 upgrade to Windows 11... Free?

My Latte Panda Delta 3 came with Windows 10 installed

Windows 10 IoT Enterprise LTSC

I previously installed Windows 11 using the installer downloaded from DFRobot

When I tried to activate it, I could not, I believe due to the type of OEM version I had installed.

I had to reinstall Windows 10

That doesnt make sense to me because they advertise it can be upgraded to Windows 11, but if I need to pay for a 11 license, the money I paid for Delta 3 including windows license would be money wasted.

I would like to try again.

If I run the Windows 11 Installation assistant, it says This PC meets the minimum requirements tro install Windows 11.

...But I am afraid I will run into the same license issue if I do install it.

Also, I assume it is better to use the installer from DFRobot which I believe is tweaked for Latte Panda.

Please help...