Theres a few ways to go about this.. if this requirement varies from page to page then i would be inclined to use the GenerateBlocks Plugin – the free version will do:
https://generateblocks.com
Then you can:
1. Set the Merged site header ( like you have on your home page ).
2. Edit the page and set the Content Container to Full Width:
https://docs.generatepress.com/article/content-container/
3. Then add a GenerateBlocks Container Block to the page:
https://docs.generateblocks.com/article/container-overview/
Yoiu can now add your background image to the Container.
Set the Spacing > Min Height to 100vh
And then build inside that Conatiner block the rest of your content.