Question for #Android experts

I'm trying to find a tablet-sized touchscreen that I can use with my OnePlus 8 Pro phone. My idea is to build a case for the touchscreen that I can slide my phone into, connect it with a USB-C cable, and essentially turn my phone into a tablet, so long as it is "docked" in the case.

BUT, I cannot find a reasonably sized USB-C touchscreen (less than 13") that is compatible with Android.

Any ideas, or is this a hopeless effort?