Apple Music app in windows flickering
I'm posting this because I found the solution. On Windows, the Apple Music app flickered really badly every time I opened it, and this also applied to other apps, like WhatsApp windows. The fix hasn't been published, as far as I can tell, so here it is.
If you're running on an external monitor like me, turn off AMD's FreeSync or Nvidia's G-sync in your monitor settings (in the OSD, operated with those buttons on your monitor itself). Not completely sure how to do it via software but switching it off from the monitor end seemed to fix everything for me. no more insane flickering and I'm not seeing any artefacts caused by switching off FreeSync.
Hope it helps!