Question about Sony Nw-E394

You don't need Sony specific software.

iTunes supports almost any MP3 player. So you can attach your Sony MP3 player to your Mac/PC and sync your music just like you would with an iPod/iPhone.

Source:
https://www.lifewire.com/do-i-need-...

However, I doubt Spotify will run on it, as it doesn't have any internet.

I have Media Go V 3.2 installed on my Win 7 Pro laptop, a Sony product that I downloaded from the internet.
I downloaded from the Internet. I found Media Go via the Sony documentation.

http://mediago.sony.com/enu...
https://musiccenter.sony.net/de...

I see that you can import the following playlist formats into Media Go:
*.asx; *.m3u; *.m3u8; *.pls; *.wpl; *.xml; *.pla.

I don't know if this answers your question, but I hope it helps at least a little.
I have no experience with ITunes & Spotify. Media Go meets my needs so far.

Greetings PM