In order to achieve the desired layout with the brand logo on the left, menu items centered, and buttons aligned to the right, I attempted to use the flexbox approach. However, I encountered issues with aligning the center items properly, as well as dealing with the wide space around the clickable brand logo.
<nav class="navbar navbar-light navbar-expand-md bg-faded justify-content-center">
<div class="container">
<a href="/" class="navbar-brand d-flex w-100 mr-auto"><img src="assets/logo/" alt="logo"></a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsingNavbar3">
<span class="navbar-toggler-icon"></span>
</button>
<div class="navbar-collapse collapse w-100 ml-auto" id="collapsingNavbar3">
<ul class="navbar-nav w-100 justify-content-center">
<li class="nav-item active">
<a class="nav-link" href="#">How it works</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Become a tutor</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
</ul>
<ul class="nav navbar-nav ml-auto w-100 justify-content-end">
<li class="nav-item">
<a class="btn btn-link" href="#">Sign In</a>
</li>
<li class="nav-item">
<a class="btn btn-primary" href="#">Sign Up</a>
</li>
</ul>
</div>
</div>
</nav>
So after some time has passed, here's how I would now address my own question:
<nav class="navbar navbar-light navbar-expand-md bg-white justify-content-center main--navigation dark-header">
<a href="#" class="navbar-brand d-flex w-50 mr-auto">
<img src="assets/images/logo-header.svg" class="navigation__logo" alt="Logo" />
</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsingNavbar">
<span class="navbar-toggler-icon"></span>
</button>
<div class="navbar-collapse collapse w-100" id="collapsingNavbar">
<ul class="navbar-nav w-100 justify-content-center">
<li class="nav-item active">
<a class="nav-link" href="#">Browse</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">How it works</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Become a tutor</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Prices</a>
</li>
</ul>
<ul class="nav navbar-nav ml-auto w-100 justify-content-end">
<li class="nav-item dropdown no-arrow mx-1 nav-link px-0">
<button id="bookmarksDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" type="button" class="btn btn-outline-secondary btn-outlined" data-original-title="Bookmarks"><img src="assets/icons/bookmark-header-dark.svg"></button>
<div class="dropdown-list dropdown-menu dropdown-menu-right" aria-labelledby="alertsDropdown">
<h6 class="dropdown-header">
Bookmarks
</h6>
</div>
...