As you know volumio is headless - you will go to have a head for it.
from my pc i have linux to control volumio from the browser.
i was never enthusiastic about the original 7 "touchscreen.
i operate volumio with my smartphone from the sofa.
in order to stay consistent in the open source world i came across to /e/.
a complete DEgoogled Android OS. i bought a used Fairphone 2 and installed /e/ on it.
I am so happy with it, that i would recommend it 
/e/ supports more than 100 smartphones. you find /e/ here:
