On the same boat with macOs, my dream would be an 13" iPad running macOs, with MBA bottom shell as battery + keyboard + trackpad + speakers + etc. But currently an external monitor (or ipad + sidecar) is the best choice. I'm also trying to work on a stand design for the second monitor, but it's not easy.
I'll do you one better for what I would want - iPhone that could slot into an iPad chassis a la Asus Padfone of old, which in tern docks onto bottom shell that contains keyboard/trackpad. The hardware is more than capable, heat output would be one concern for sure. I wouldn't mind a Mac that is even 70% as fast as the M1
Tried this with a galaxy s10e with magnetic dock attached to the back of a 10.6" 16:10 2560x1600 touchscreen display, and it went well, however software support for a desktop mode (DeX) was still lacking.
