If one decides to keep roon as the main music library then what is the best way to decommission the Sooloos Library? Should I just delete the music folder but keep the qnap app installed and running for updates?
Up to you. Make sure all your music has been exported before deleting.
I would check for non-contiguous files and corrupted files using Roon before you decide to delete.
Keeping thre Sooloos app running will keep firmware up to date on any Meridian end points.
I will double check everything then delete to free up space.
Keep in mind you don’t need to run a Sooloos core to update zone firmware now. The config app will do that now.