By way of design the header of my document looks like this. The <h1> is buried in an <ol>. It's still the first heading tag of the page but will it lose any of it's SEO value compared to it just sitting on it's own as the first tag of the body?<body>     <header>  <nav>   <ol>    <li><h1><a href=>Company Name</a></h1></li>    <li><a href=>About</a></li>
Main  tag is embedded in an unordered list. Will this affect SEO?
seo;html
That <h1> will be the heading for the <nav> section and not the page as a whole. <nav> is its own sectioning element and won't affect the page's SEO.