Can I set my Section Banner at Full Bleed, without my Header inheriting its design?

Site URL: https://bluebird-porcupine-yzdg.squarespace.com/collection-3w5d7-1

Hello, is it possible to set my first section banner at full bleed across the page, but without the header inheriting the section banner design?

I would like my banner set at full bleed but I still want my header to have its current white background before scroll.

I tried to add a 'dummy' blank white section under my header but this makes the gap between my header and first banner too big! See attached. I would prefer it to be more like as image 2

Page - https://bluebird-porcupine-yzdg.squarespace.com/collection-3w5d7-1

Pword - bluebird

Many thanks,

Best,

Faiz