Termux, Andronix and (Wireless) Dex (Samsung phones only) work pretty well to bring a workable Linux desktop onto an external screen, with the phone as a separa

Termux, Andronix and (Wireless) Dex (Samsung phones only) work pretty well to bring a workable Linux desktop onto an external screen, with the phone as a separate screen for android. You can also connect a usb-c hub if you want hdmi in and out, network etc. It's even possible to drive 3D printers directly over USB. As an additonal bonus, for Galaxy Notes and some newer S devices you can use a stylus for art, signing PDFs etc. They also support splitscreen multitasking and virtual desktops which is quite practical if you work from the terminal (emacs). Certain phones can be very good replacements for a computer if you require the portability.