Transparent Header

Not sure what you mean?

It should be transparent if you remove the hex code in the field or click clear.

Also having an issue with header transparency, the background color under the header section in customizer is set to completely transparent but there is a white background still coming through. The nav section transparency seems to work as that is coming thru fine when I scroll down (using the sticky option).

This is the site:

https://levelcreativ.com/clients/secondhome/

Not sure where this white color in the header area is coming from? I've gone through all the areas in the colors section in customizer.. am I missing something?

That white area if your body background.

You'll need to do this if you want to place your header on top of your Elementor section: https://docs.generatepress.com/article/merging-header-navigation-content/