I think Francois might be correct in hinting that your Synology has a UPnP server running which your other devices are automatically finding (since you did not talk about having to enter network mount information), while the BR-20 is looking for an SMB network share. The BR-20 will look for SMB shares on the local network, which should automatically pop-up under the "NAS Setup" > "Add Share" > "Devices" pop-up menu. You can also manually enter the SMB mount information on that screen.
Regarding Qobuz, there is a "Qobuz" > "Sound Quality" pop-up menu you could double-check. I selected "Studio" from that pop-up menu and successfully played back 24-bit 44.1kHz, 24-bit 48kHz, 24-bit 96kHz, and 24-bit 192kHz.