I missed it. Life's too short to get mad with people on Internet forums.
I was explaining what this software does in its back-end. What you are showing above is the web-based front-end of the app. Effectively, the NAS management software is allowing you to see when directly logged into it's web-based management capability, what is going on below the user stack. I also have the same GUI above when logged in to the management console and have had ever since I installed my Synology almost a decade ago. Mine does not have a USB option (current v7) and I don't recall ever seeing it. But that might be because my Synology is old.
Via wired or wireless packet network I can get to my audio files via two principle ways - (1) via CIFS/SMB mounting the generic file Network-Attached Store (NAS) which requires nothing fancy at the NAS end*; and 2) via DLNA/UPNP which is delivered by the Synology Media Server (which is not a generic NAS-type service but an add-on that runs in Synology's host-services environment). Also, the inbuilt indexing services ensures that the Audio and Media Server content lists are up-to-date. My streamer works using the (1) CIFS facility and I can also listen on my smartphone via DLNA using (2) and the Synology DS Audio app for Android.
* I have experience in procuring and analysing data-centre-scale file storage (effectively NAS) and block storage. There are things that a generic NAS must do, and running audio drivers on a USB interface is not one of them. But some domestic products may do so as an added function of their host - this is one of those YMMV things.
What others have said makes a lot of sense: if you roll your own NAS using an old PC/Laptop etc or a Pi, these are rich hosts which can have all sorts of extra benefits. For a direct NAS to DAC with the least number of connectors, there's a lot to be said for this approach rather than an off-the-shelf NAS device where they may not see enough profit from adding in what is quite a niche requirement.
OK, I read it. It was helpful for some additional info, but you know already I managed to get the USB-DAC to work. I've seen your like on my other thread, thanks, so you've seen it. I'll move the topic over there.
Side info; I access my NAS wireless, this was the main reason I got it. As a wireless - (ly) accessible audio mass storage. I can let all my guests pass through and either play music or share something. The whole idea of wireless loses its meaning if you still need to have some sort of cable going from your PC, in my case laptop, to your Stereo. (It's an old Stereo, so no BT, Wi-Fi or any such things) And this is why I came up with the idea to go NAS straight to the amp. It wasn't as easy for all the reasons you've already mentioned. (It's still "in-the-rough" since to play music the way I do now, I have to keep creating profiles on my NAS. Still, I don't have THAT many friends.)
The original idea was also to use this step (between NAS and amp) for room EQ. Otherwise, it's getting messy. I guess you could go PRE OUT > MiniDSP (set it up) > MAINS IN. I'd rather bypass that step as it seems more neat to me to put it between NAS and amp, since that step needs to be there in my way of setting it up, anyway.
And this finally sets me free, I can move around my house with my laptop as I usually do - I work in my living room, I get up to do some cooking, I go to another room for my projector etc. and I can play music from wherever. And I can still play some movies from the NAS over my laptop and on the projector. It runs smooth, it only takes half a second for skipping.
