Some questions about players and Media Server on a NAS device

I am looking to build a Plex Media Server on a NAS box I can leave on all the time. It would be for music ONLY, no movies or any other media. Any recommendations? I would prefer SSD drives, probably 500GB - 1TB.

Also some issues I am dealing with:

If I run the Plex app on my ROKU, the first beat of every song gets cut off, which is slightly annoying, and there is a pretty lengthy gap between songs (1 sec or so), which is expected since there is no gapless playback. I run my ROKU into a Marantz AV7702mkii preamp.

I can access my media server directly on the Marantz preamp, and the issue on the ROKU is pretty much eliminated - very little lag and beginnings of songs are intact. However, FLAC and WAV files do not play on the Marantz for some reason (I get a file format error). The ROKU plays both formats fine. I would not think that this preamp would have an issue with WAV files… it is only 1 year old - but I could be wrong. Most of my music is in AAC 320 format anyway, and from a quality standpoint my ears don’t hear much difference if any. But if anyone has ideas about fixing that, please let me know.

Cheers,

Mathias

According to Marantz it should not have a problem with FLAC or WAV…