I've found a workaround that works for me in Manjaro about 80% of the time, while it is a bit sinful for any Linux user: If the screen hasn't turned white and unresponsive yet and is still just frozen, you should be able to do some basic stuff like pressing play or pause as long as you don't resize or minimize the window. To unfreeze the window, click on the advertise, that will open a tab in your browser and will refresh the Spotify client.
This makes me think the problem is triggered by an error on the advertising system. I guess a console log should be inspected to check that.
Another user posted that they could unfreeze the UI by dragging the song title in the now playing. This works for me at about the same frequency (~80%).
I have Spotify Premium, so I can't confirm that it's ad related, but I think interacting with certain UI elements unfreezes it for some reason. Might work with other parts of the UI, maybe playlists or friends list? I'll have to experiment next time.
I have this problem too, UI freezes but the client is still responsive to clicks and music keeps playing. Reinstalled and tried snap instead but the problem persists. The trick of dragging the song name works for me to unfreeze, thanks for the tip!
I noticed that too, about the dragging drop trick... if you click anywhere inside the spotify window and move the mouse (like drag-drop) - even when the screen blanks - it just back to normal. Thats very weird, but its a reasonable workaround meanwhile..