Kind of weird that nobody's talking about getting rid of the hardware? An ESP32 that streams compressed audio over a mobile connection is all you should need to replace the "smarts" in a cellphone. Have a remote server do it all, and the local device is just a glorified mic and earbud. Give me a clickwheel and an audible user interface and I can do 90% of what I use a computer for.
Because that sounds terrible? What would I use this for? Reading email or browsing the internet? I can read faster than an AI can dictate to me. Though I'm sure I could adapt somewhat, as I understand that people using screen-readers are already able to use them quite quickly, I don't really want to. I can't play my favorite games via an audio interface, I can't watch a movie, and just about any attempt at using such a device for work would be compromised by the knowledge that I'd be able to do the same thing more efficiently with a keyboard. Heck, just the idea of verbalizing commands means I probably can't use it for work outside of an office, because I can't exactly go around in public verbalizing company information every time I need to get something done on the go.