You will want to wrap the sidebar and content elements within a two new div’s from what I understand from your initial post?
The sidebar wrap could look like this:
<div class="my-custom-sidebar-wrap">
<div class="sidebar left-sidebar <?php echo esc_attr($width); ?>">
<?php dynamic_sidebar($left_sidebar); ?>
</div>
</div>
The main content wrap could like this:
<div class="my-custom-content-wrap">
<?php while ( have_posts() ) : the_post(); ?>
<?php wc_get_template_part( 'content', 'product' ); ?>
<?php endwhile; // end of the loop. ?>
</div>
If you are not familiar with HTML/PHP it maybe best to work with a developer to integrate these changes. The default masonry layout for this case is to wrap the products around the sidebar for a true fullwidth masonry effect.
The changes you are looking for are not a simple task as such.
Thanks,
David.
.