I would like to start by saying that Volumio rocks but sadly I am not a programmer an I can’t customize to my taste.
I am inviting you to entertain looking at an optionally choosable interface optimized for Auiophile listening enjoyment environments.
I have been using a program for years called Album Player which I use with an ELO 19 inch touch screen . When it comes to player interfaces, these guys just have it figured out and it is an extremely enjoyable experience. Unfortunately it runs only on Windows and I haven’t been able to get it to match the sound quality that I can get with Volumio using MPD on a PI-3 with external DAC.
I would like to encourage you to have a good look at Album Player and enlist some design queues from it and come up with an interface for us audiophile types.
I would like to reiterate that I think Volumio is fantastic and works terrifically on my iPhone. I and several of my audiophile club members just long for a little something more.
Thanks for listening.