Issues with syncing iTunes music library with Synology NAS

Just took the plunge and bought myself a new Synology RS822+ NAS.

First thing I decided to do with it is to move my music library from my (Windows 10) PC's internal drive to the NAS. I typically listen to music by giving my Sonos system access to the iTunes library on my PC so I have access to all of the playlists I've made over the years....this has worked great, but obviously requires that my PC be powered on and not in sleep mode pretty much 24/7, which is not ideal.

This seemed like it would be pretty easy: I copied the music directory to the NAS, edited the iTunes XML file to point to file locations on the NAS instead of the local drive, rebuilt the iTunes library from that, and redirected Sonos to the new directories on the NAS. Two days in, and so far this part is working great, I have access to all my files and playlists even when the PC is off.

BUT!

I have lost the ability to sync my devices (iPhone 10 and my beloved iPod classic) with iTunes. When I plug either one into my PC, the normal sync process starts, but then just stops partway through without any actual syncing happening. My brief internet search indicates that iTunes and NASes tend to hate each other and have for years, so I assume that's what I'm seeing here.

So...

1) is there any way I can fix this sync issue, or is that just permanently dead as long am I'm storing my library on the NAS?

2) is there some other way that I can accomplish what I'm trying to do (have access to my music files and iTunes playlists from the NAS) that I'm overlooking? I kinda feel like this is one of those situations where there's a simple solution I'm not seeing.

Of note, Synology does have an "iTunes Server" add-on, but documentation of what it actually does is VERRRRRY thin, and I'm leery of going with it if it's going to make me rebuild the library from scratch (which would take weeks if not months) and if it might not even solve the syncing issue.

Thanks!