https://monitorsanywhere.com/ has moved to an Android device (not the plus version pictured) for its video walls.

Here is a link to a review (sorry about its advertising) https://androidpctv.com/review-x96-max/#PRODUCT_DETAILS

Windows only software for extending desktop to this Android device. https://spacedesk.net/

Android sits on top of a Linux base OS. Its directories are organized differently than other Linux distros. Here is the root of its file system:

You can replace the provided OS with Debian Buster installed on a MicroSD card. https://docs.armbian.com/