[Troubleshooting] Windows won't sync new music from phone

[x2NaTe2x]

Hello guys. For the past couple of months, I've been having some issues where at least once a week, I have to un-install and re-install Spotify on my Windows 10 Desktop. New music that I save to my library via my iPhone X won't get synced at least once a week to my desktop. It's very annoying. I have looked the issue up, and try the method to put both devices in offline mode for 5-10 min and then restart each, doesn't do anything for me. To fix this, I literally have to re-install Spotify, and it happens about once a week. 

My desktop is running Windows 10, and I am a Premium member. I have used Spotify for more than 2 years, and used to never have this issue. 

Any ideas?