Do you want the background color to be white for the logo and extend full width?
If so, try follow the below steps:
1. go to customizer > layout > header, check the Use Navigation as Header
box.
2. go to customizer > layout > primary navigation, select full width
for Inner Navigation Width
3. go to customizer > layout > header, uncheck the Use Navigation as Header
box.
4. remove the CSS I provided here: https://generatepress.com/forums/topic/problems-with-header-and-primary-nav/#post-2199814
5. add this CSS:
#sticky-navigation .navigation-branding {
justify-content: center;
background-color: white;
width: 100%;
margin: 0;
}