I already have my eye on doing a hotspot from the Calyx Institute and then whatever devices I fancy that have WiFi. I have a phone sized e-reader I already do this with using my phone hotspot, so I’ve considered just making that my norm.
I’ve also got my eye on a few Linux handheld projects for the same reason, and honestly I might lean toward those so I can get more modern hardware. Could potentially incorporate a usb cellular antenna with a Linux handheld to streamline the tethering process.
I recently found a window manager for Linux that is designed for phone sized displays. I’m forgetting the name at the moment, but I’ll come back and update this once I find it.
This is almost exactly what I’m after. Will probably pick one of these up and experiment with flashing it. The big assumption I feel like is that the keyboard just registers as a normal HID/USB device and will work with any os. Fingerprint and stuff could be fiddly, but we’ll see.