Hello, @lew-shop,
1- From the Theme Settings you can set the site layout, please see the image: https://postimg.cc/N5MJd0Mr it will work for the entire site. If you want to set a page to full width simply edit the page and from there you can set the sections/row to full width/stretched sections see the image: https://postimg.cc/64sWYPV8 that’s all.
2- For the breadcrumbs, you can simply enable or disable it from the XSTORE >> Theme Settings >> Breadcrumbs >> see the image: https://postimg.cc/sBQCqcg7 and https://postimg.cc/8F6PMDW2
3- You are editing the page with Elementor and the default of Elementor has no full width which is why it shows the page layout to box see the image: https://postimg.cc/hzbfHg2k
Regards 8Themes Team.