Display configurations for HDMI TV output

Lately I’ve started struggling with HDMI > TV with my plasma laptop.

The display configuration that I want is separate display but you can push windows to the right (or, sometimes it’s left) but I don’t think “extend to left” or “extend to right” is quite right. These give a black screen that displays mouse pointer but not windows. What I want shows a mountain background by default and does work. Although it doesn’t correctly guess the TV resolution, but that problem is secondary for now.

The audio also doesn’t select the TV automatically any more. Choosing it requires going into System Settings > Audio > Playback Devices and selecting port and profile.

I can’t seem to find a place online to explain what I should be doing now to restore the old default behaviour that I know and like.

Thanks in advance!