"Connect to a device" not showing other devices, combined with "Can't play current dong"

[nihie]

Plan

Premium & Headspace

Country

Norway

Device & Operating System

Samsung Galaxy S9 (Android 9) & Windows 10 Pro (10.0.18362)

My Question or Issue

I've had the "Can't play current song" issue for a while, and I've been trying the different suggestions for solutions, but nothing has worked (reinstalling, the host file, hardware rendering etc.). And now I wanted to try to play music from my phone, and then continue playing on the desktop app, but my account is not syncing. It has been like this for a while also. I cannot see the music playing on other devices, and do not get the option to control them on "this device" like I did before. 

I also wrote a lengthy post about the "can't play..." problem here, though I cannot see my own post at the moment.