Thank you very much for your support to N5ii, Glad you like it and has a fairly positive experience so far.
You have mentioned "It has it flaws as once it plays music like faster than it should", I am not sure what exactly is the problem and how to resolve this for you. Do you mean the "pace" of playback is not correct? A 3 minute song will finished in 2min 50 sec when playback by N5ii? If this is what you have experienced, can you tell me more detail about the music files that you are using? Format (WAV, FLAC, ....), Bit rate, sampling frequency (e.g., 24bit/96kHz). etc.
If you are not familiar with the technical detail of your music file, maybe you can take a photo of the music property page in N5ii, just select the music file that play faster then normal and following the following steps to display music property: