I feel like what's missing for me to be able to use my phone or iPad for development is a good keyboard, maybe like one of those old slide out keyboards, but those are not made anymore :( Even so, swipe to code could potentially be faster than using a physical portable keyboard.
Clicks is also interesting, though it doesn't have separate keys for symbols like `;`, that's common with those tiny keyboards.
Combined with AI autocompletion (Copilot) and remote VS Code (already possible with Blink or just a browser), I feel like coding on a touch device could be made comfortable. It doesn't have to be as painful as it is right now.
However there's a big difference between a "generic English swipe keyboard" which can be calibrated to a single dictionary used in many places, versus a swipe keyboard that might have to offer very different suggestions based on the current programming-language and on what variable or method names exist within a given scope.
If you had a swipe keyboard tailored for one language, that'll only help complete common keywords and core APIs, but any real project will have a lot of "new words" that it won't know without some deeper IDE-ish system.
You could also pick up a PinePhone with the clamshell keyboard attachment (although for some reason I can't find the keyboard on the Pine64 store).