Personally, I wouldn't bother introducing a word besides "phone," because we shortly won't be carrying one single device like this anymore. May as well just keep saying "phone" for the few years left.
What will replace phones that soon? Are you referring to smart watches and wearable tech? Wont we still use a phone as a primary device to tie it all together?
Smart spaces (public and private) and much simpler devices. People are likely to carry basic phones or devices that can serve that purpose, but we probably won't all have what we consider a smartphone today.
Gizmodo tried to suggest "com" instead of "smartphone" about 10 years ago: https://gizmodo.com/5061705/smartphone-is-a-dumb-word-we-nee...