I would recommend you choose a full width theme and use SiteOrigin plugins for making custom layouts very easily
Themes:
https://en-ca.www.ads-software.com/themes/athena/
https://en-ca.www.ads-software.com/themes/onepress/
Plugin 1: Page Builder by SiteOrigin
Plugin 2: SiteOrigin Widgets Bundle
Page Builder by SiteOrigin tutorial:
https://www.youtube.com/watch?v=mL6iIV7JxLo