generate_before_main_content Hook Shows Underneath Content

Hi there.

I am trying to insert a metaslider into the top of my home page using generate_before_main_content hook
Trouble is that the content displays on top of the slider.
See https://www.aroundwellington.co.uk/wp-content/uploads/2021/11/hooked.png

How do I move the content down?

Kind regards
Damo