Use TV to watch family content. Use iPad for personal things. Phone is for music. Speaker with home assistant is for music too. Buy gadget for every use case. Replace them regularly.
I use a computer to do my job, and my pet projects. While media players and especially music players have evolved in the past years with all those new devices, desktop players are mostly the same: iTunes (now Music) and Winamp.
Avacia’s main use case is to play a video in a window. A window will change height to preseve video aspect ratio. You can use shortcut to resize video window to 1/3 or 1/4 of screen. Music support is available by «wny not?» principle.
If you want fullscreen, use your TV or iPad. I’ve tried to add support for full screen, but failed.