I do on a Pixel 3. Sometimes I'll SSH into my desktop, sometimes I'll work on it directly, both using tmux and vim. I love everything about this setup except the screen size.

I use an original Google pixel and a cheap $20 keyboard and have done some basic scripting etc on it.

Main problem is tmux doesn't work well on it. Otherwise vim is pretty great, for example. It's actually even pretty usable without the Bluetooth keyboard thanks to the volume keys being a fn layer and ctrl

emacs works pretty well. even the touch scroll gestures are translated into scolling in emacs. and changing the buffer by touch also works. so you can use emacs eshell and a keyboard and it is perfect.

Emacs does work pretty well in Termux, but on Ubuntu Touch you can run full X11/GTK Emacs, which is nice. (I suppose you could do the same thing via Termux with an X11 session.)

These GNU tools are really optimized so they will work well on even the cheapest Android phone. If you are comfortable with the small screen it should work.

use this setup daily Without a Bluetooth keyboard. Buy any modern android from blackberry (before they go out of business).

the keyboards lack esc, tab etc. but since they have a ctlr key yoiu can work around most of that. If you can still find, the best keyboard layout and performance is the priv model. avoid the Key2LE.

i use hackers keyboard because it has all the needed keys like control and alt and it works very nicely together with emacs. or you can startup jupyter notebook and use firefox as front end.

works well for me with a nexus 5x and foldable bt keyboard. also if you have a google chromecast you can turn any hdmi monitor/tv into your display. you can zoom in and out by 'pinching' in termux and make the text suitable for any display