This isn't so much to build on your idea directly, but maybe some additional fodder will help further inspire ideas and yet more food for thought (for myself as

This isn't so much to build on your idea directly, but maybe some additional fodder will help further inspire ideas and yet more food for thought (for myself as well, and better yet, anyone else).. I recently realized I can use a $15 USB capture card with an HDMI input on the other end to snag the video feed of a Pi or anything else that can output HDMI. As I use Linux, you can tap into the /dev/video<number> device as if it was a camera, using VLC/OBS. (There's also a paid app on Play store that allows me to also do this on my phone as the display side, using OTG. Would love to be able to use my tablet running a de-Googled LineageOS as well, but that'd entail figuring out how to crack/patch out Google's license checking library, and I haven't found any FOSS alternatives, ugh.) From there, making the (my) dream happen would be if there was some convenient way to use the same device that's tapping into the video out as the keyboard/mouse input, much in the modal way of VMWare/VirtualBox, where it overtakes your input, and using the hotkeys to release when you want to switch back to your tasks on the host. In particular, I have a Flipper Zero that doesn't get real use beyond novelty functions and have been wondering if that (or something like a ESP32/ESP8266 computer) could help facilitate that. My skillset is nowhere near that close to the metal. At least, re: your post I'm piggybacking, and coming from knowing the capabilities of the Flipper Zero, I wonder if RubberDucky/BadUSB payloads could bring you any closer to meeting the spirit of your goal. Or, some sort of rsync like mechanism baked into the Pi when it (automatically) connects to a detected, saved network. Or, a RubberDucky/BadUSB payload on-demand to fire off an rsync.