~~Apple Music web isn't working on Vivaldi, which settles it, I'll have to use Spotify on desktop I guess.
Yes, Widevine was working on Vivaldi.~~
turns out, you can just restart the computer and it'll work. Also used Chromium (which needs Widevine to be installed, chromium-widevine is the AUR package you need), but I fail to see how this'd affect Vivaldi.