As there seems to be some interest in the forum on this topic, I wanted to update my initial post with some positive news.
I managed something of a work-around. If I launch MC, then launch a properly set-up Minimserver 2/Minimwatch 2 to index my external hard drive for files, Bubble, once set up to work with both MC 27 and Minimserver on my Android phone, will recognize all my files and playback, at the correct resolution, is achieved. In Bubble, the library should be set to Minimserver and the renderer should be set up to recognize MC. And make sure you select gapless playback in Bubble. So, I am operational. What this means, for instance, is where I have a folder for my Beatles original English vinyl pressings that have been ripped to 192/24, Bubble will see that folder, once you select "Folder View" in Bubble, allow me to open that folder and then select a specific album to play back.
Still, I'd like some input from MC tech people if there is some way to configure things where I don't need Minimserver in the chain and can have Bubble, or some other Android App., work directly with MC and the Questyle DAC.
Also, please note, I am very much a novice at this, so I don't feel qualified to answer questions about this and how to make this work for you.