Hello, I got my hands on a Volumio Primo. =)
So far so good. The Primo is connected with HDMI to a 32" QHD screen.
My problem for which I have not been able to find a solution so far.
I’m almost blind and the UI on the screen is tiny af. 
Is there a possibility to adjust the scaling of the UI or the resolution manually?
That would be a great help!
Volumio Version: 2.915
Hardware: Volumio Primo + Primo HIFI Edition?
DAC:
Using UI may be much easier on computer or on phone. Computers and phones have built-in screen magnification support.
Nop, i give up on this idea.
I use now a 12" Tablet but the scaling from the Volumio app is still not the best. Most of the time. i use the accessible mode with tipping 3 times on the screen for a zoom in and with two fingers scrooling to move the image section.
Would be nice the have a screen on top of my Audio Rig thats shoes me what i playing right now, but this i gues is just possible with an moddified ui verion für me and i dont have the programming skills in this programm language.