LibreELEC / WeTek Core / Audio output configuration settings not visible

Hello all. I am using LibreELEC 8.0.2 on WeTek Core.

Problem: In Settings, I do not see Output Configuration setting under Settings -> System -> Audio.

Why is this a problem?: I would like to set it to Fixed to speaker configuration 2.0. This way, I don't have the low centre speaker volume issue on video files with 5.1 audio.

Notes WeTek Core is connected to a TV with HDMI cable. I do not have external speakers.

Is there a way to make this setting visible? If not, is there a reason for this setting option to be hidden?

Thanks in advance.

Quote from JohnWB

Do you have Expert selected as the advanced selections will not be visable otherwise.

I can only select Advanced. There is no Expert. From Advanced, it goes to Basic.