I have googled and googled, sorry in advance if already answered.
I have Roon core on my Windows 10 HTPC set to auto start in full screen. I play music on the core machine but select the music from my phone. Is there a way to have my HTPC display the current album that has been selected via the remote app?
You might try linking the core with the zone you are playing so they show the same thing.
You can then adjust volumes of the core and listening zone if you want.
If you set the HTPC to “what I call” theater mode, you can do what I think you want. Go to the Queue screen and select the option I have circled in the pic.
If you add songs from your phone to the queue the currently playing song will be displayed on the large screen. There is also an Up Next in the top right.