Whilst it may appear this question has been asked before concerning mobile and desktop versions of navigation elements, it hasn't in this way.
It was established in the accepted answer to the below question that having duplicate content inside a <nav> with one visible on mobile and another on desktop (via breakpoints) was not likely to negatively impact SEO.
SEO - Responsive Website and Duplicated Menus
On the assumption that the above is still the general consensus (please advise if not), then how about a slightly different setup.
- A hamburger menu that contains 5 major links and 5 secondary links.
- On mobile the hamburger menu is made visible via a toggle button.
- On desktop the five major links are also visible in a sticky nav bar. When the hamburger toggle button is pressed the sticky nav bar animated away and the same nav bar as on mobile with both sets of links is made visible.
See this image:
Stylistically this suits the user experience we want, however, it will duplicate the 5 main links inside the nav bar in code. The nav bar items and those in the hamburger menu will not be visible at the same time but the will use css transitions to fade the nav bar out. So technically there is a duplicate of major links here but it is not being used to cheat SEO. It is merely a design choice.
Is it too much of an SEO implication?
Code concept:
<nav>
<div class="nav-bar>
<a href="/something/1">Link 1</a>
<a href="/something/2">Link 2</a>
<a href="/something/3">Link 3</a>
<a href="/something/4">Link 4</a>
<a href="/something/5">Link 5</a>
<button>Hamburger Toggle</button>
</div>
<div class="nav-full>
<div class="nav-full-major">
<a href="/something/1">Link 1</a>
<a href="/something/2">Link 2</a>
<a href="/something/3">Link 3</a>
<a href="/something/4">Link 4</a>
<a href="/something/5">Link 5</a>
</div>
<div class="nav-full-secondary">
<a href="/something/6">Link 6</a>
<a href="/something/7">Link 7</a>
<a href="/something/8">Link 8</a>
<a href="/something/9">Link 9</a>
<a href="/something/10">Link 10</a>
</div>
</div>
</nav>
