Basically the title, I want to use my laptop, which uses Arch Linux, and my tablet, which is an android one, as an external monitor for my desktop pc.
I don't know how to set it up, but using a sunshine server on the desktop and moonlight client on the laptop/tablet might be a solution.
Might be possible with Intel's new Thunderbolt Share, but you'd need some hacks to make it work with present-day hardware and it hasn't been released yet.
I've gone the x11vnc on a dummy display route, but found the setup's too much ceremony to want to use with any consistency.
Deskdock + barrier/synergy is slightly more ergonomic -- your laptop mouse and keyboard redirect to control android when you move the mouse out of the laptops screen and onto the tablet, but both displays are showing their native OS.
It's entirely tangential (not for android, not just a screen), but arcan does some cool stuff in this space. Here's a video of "sever tunneling" https://youtu.be/jIFjzN7dk10?t=107 (fancy x11 forwarding; It looks fascinating, but I've never gotten it setup).
