1. the GB Button that you have added using a block element, edit that.
1.1 Select the Buttons block – thats the outer wrapper not the button inside it.
1.2 Remove the Top and Bottom Margin.
1.3 Increase the Top and Bottom Padding, to make the button the height you would like.
2. In Customizer > Layout > Primary Navigation, increase the Menu Item Height so its matches the button.
1. the GB Button that you have added using a block element, edit that.
1.1 Select the Buttons block – thats the outer wrapper not the button inside it.
1.2 Remove the Top and Bottom Margin.
1.3 Increase the Top and Bottom Padding, to make the button the height you would like.
The button David referred to is the black backbutton, this button is added using a block element – hook, you can find it at appearance > elements. https://www.screencast.com/t/4thds2RsKdaB