If you are storing Hi-Res music in flac and very few in DSD, like I do, the file size will be significant. In my case, my collection is around 2 TB (around 50,000 songs). I will require around 2900 CD to store music. Even around 500 Gb will require around 700 CDs to store music.
There is nothing complicated about a NAS device. Most wifi routers now days have a usb 3.0 port and support a hard disk attached to it to be shared and can act as a NAS device. A single hard disk connected to it can easily store all your digital music content. Even a laptop can have a shared drive enabled, regardless of the OS, and act as a NAS. The advantage of a NAS as opposed to a direct attached storage is reduction of digital noise. Even SSDs solid state devices have dc-to-dc converters and have digital noise. Even the mechanical hard drives have noise. So it is best that the music source access the files using a protocol like NFS, SAMBA or SMB protocol as opposed to direct attached storage. So one of the ideal setup is to have the following kind of setup
1) The device that has the DAC should be powered by a low noise power supply (like linear power supply) and access to files should be through network and not through a direct attached storage. For the technically challenged, there are ready-made devices which can mount any shared drive and one can connect a good DAC to it like the usbridge player https://allo.com/sparky/usbridge-signature-player.html
2) Any computer, laptop or device that supports file sharing. This device can have the hard disk attached (ssd, hard drive, flash drive, whatever rocks your boat).
3) A network, preferably a gigabit network. If you already have a router, it will mostly have 4 gigabit ports on it. You just have to connect 1 and 2 to this router and you will be fine. One can also use wifi to have 1 and 2 connected. Wifi N is good enough to support even DSD playback.
