on page seo duplicate content

Imagine you have a new site, looking to white hat it all the way to million-dollar company. Before all of that cash, you are sitting with ~5k budget to spend on content. You know your website sucks on authority right now so you are looking to target long-tail zero competition keywords. But...

Hey guys, I build all my websites with WP Page builder and absolutely love it. My question is, do you know if Google would perceive copied sections that are only visible on Mobile, due to mobile responsive design, as duplicate content or does it know that it's only visible on mobile and not...