Connect to Synology NAS iTunes library from iPhone

Hi All,

I have my Synology NAS set up with Music library and iTunes server running. On my MacOS computers I can detect, select and play the music library on the NAS (casting to my Sonos system, all on my home network). However, despite working my way through a number of posts and FAQs I do not seem to have a way to detect and select my NAS music library on my iPhone when connected by wifi to the same home network. iPhone 8 running iOS 15.5.

(Of course if I could get the Sonos app to connect directly to the NAS that would be a whole other way to solve this issue but that's six months of misery and frustration already..).

Thank you in advance!

best

Beej