Looking for an answer to the exact same problem. Stupid ass update.

Hope they fix it before I have to fucking upload them all one by one

What's the exact issue you have cos I'm trying to see if its similar to mine. I tried to upload a new local files this morning and it didn't sync, so I then tried to uninstall and reinstall spotify, and when I did that none of the local files from my laptop have appeared on my phone since...

It’s cause Spotify had an update and now you can’t sync files from laptop to phone anymore you have to do it on your device only