I'm not sure what you mean about blazing speed and Emacs. Emacs is not a modal editor and isn't intended to increase your typing or code editing speed anymore than any other text editor.

I think people assume that Emacs is a modal editor like Vim but I'm not totally sure why that is.

Otherwise I agree that the mobile input methods are simply too limiting to work with.

Moving around the cursor is pretty difficult and accessing non-alphanumeric symbols sometimes requires clicking the "modifier" thing once or twice.

The on-screen touch-driven keyboard also takes up at least half of the screen, and shrinking it makes hitting a specific key much more difficult.

There is also the difficulty in holding the phone while doing all of this!

On Android you can connect a regular keyboard to the device and use that, then I think working on stuff could be viable!