If the OP really objects to using Roon, an alternative is to add a Meridian 210 to the 818.

Transfer the music library from the NAS to an SSD connected to the 210’s USB/UPnP input.

Download one of the usual apps (such as mconnect) for playback.

Not an Actor, nor married to Jamie-Lee Curtis.

#1: DSP5200SE|DSW.2|218|210|506.2|504
#2: Prime/PSU|SOtM sMS-200 Mini NEO SE|Focal Stellia
#3: Other stuff