How to install desktop Ubuntu on your Android device - I tried it and it works really well with LibreOffice, desktop Chromium etc

The only requirement for this to run is a rooted phone (which my Pixel 2 XL is) and the instructions were pretty easy to get Linux Deploy to work. Once that was in I could choose from a variety of Linux distros such as Ubuntu, Arch Linux, Debian, etc and depending on which one, then also the version and some desktop UIs. Its not everything as I noticed I could install latest Ubuntu with MATE desktop but did not see Kubuntu by default, although I see there is a custom option too.
Internet browsing and app installs are working fine, but I was having trouble mounting a local folder on the phone to browse its data, and also to browse my computer. But I could access my Nextcloud server and get files from there. It works perfectly fast enough.
To be honest a phone's screen is a bit small to do decent work on, so I see two useful scenarios maybe for this:
1. Boot it as-is and display via Chromecast to a TV screen, and just connect a Bluetooth keyboard/mouse to operate it. https://squeet.me/objects/962c3e10ee29882c837a5fd3a2289414edf77a27