You can insert widgets into a post by Shortcode. Just make a shortcode with dynamic_sidebar()
function to insert your specified sidebar widgets.
<?php
add_shortcode('sidebar_widgets', function($atts, $content) {
ob_start();
$atts = shortcode_atts(array(
'sidebar_id' => '',
),$atts);
?>
<div>
<?php dynamic_sidebar($atts['sidebar_id']); ?>
</div>
<?php
$html = ob_get_clean();
return $html;
});
You can implement this shortcode with any page builder plugin.