Local files in QNAP NAS: bad performance

[pachero]

Plan

Premium

Country

Sweden

Device

Macbook Pro 16-inch 2019

Operating System

macOS Catalina 10.15.4

My Question or Issue

Hello, I have +21.000 local files (mp3) stored in a NAS. I have added them into Spotify via local files. What happens is that the performance when playing these local files is very bad. In the beginning it seems to work well. After 1 or two songs, if I try to pause the song or skip it, it takes ca. 1 minute for Spotify to react. Also, for example, if I try to browse elsewhere in Spotify (an online playlist), it will not show, it sort of crashes. Quitting Spotify also takes much time. In the meantime, the MacBook fan starts going really fast and loud.

Are there any best practices on how to make Spotify work together seamlessly with such an amount of local files (+21.000) in a QNAP NAS?

Otherwise I'm thinking about using iTunes instead for this purpose, but I'd prefer to use Spotify!

Thank you very much.