Yes I can provide very precise instructions.
1. Get Rufus
2. Use the Image downloader feature part of Rufus and download 20H2, the December one, English, Education Edition.
3. Mount such image in NTLite, mount Education N, in particular.
4. Load the Lite-Safe99999 preset..
5. Process it.
6. Put it on USB, install in real machine (tested in real machine), Sandbox works.
ALL other presets fail, and most interestingly have a tendency to fail with new error codes, particular the last 5 presets with Lite-Safe99999 being the last. I interpret it as MS giving the middle finger, exploding the sandbox API(not the API but all the backbones) all over the place deliberately.
And rest assured Garlin that sandbox compatibility is not assured by "App Guard/Containers", like not even close.
It's annoying complicated, but I did greatly narrow it down turning a huge problem into a manageable one.
The preset before Lite-Safe999 was close to success. I know 100% it related to drivers for that preset, but did it only relate to drivers somebody only as knowledgeable as nuhi could answer easily.
Please remove the attachment once you have it in hand.