Blog Pagination Not showing in my custom template - wordpress

Question

I created a custom blog template in my WPLMS Wordpress theme, with wp-query. But I'm unable to show the pagination. I tried to build a shortcode its working fine but in the last im unable to show my pagination.
//blog section 2
add_shortcode('da-blog', 'da_blog_post');
function da_blog_post($attr, $content = null){
$attributes = extract( shortcode_atts(array(
'title' => 'blog post',
'subtitle' => 'latest news',
), $attr) );
ob_start(); ?>
<section class="exthree_blog">
<div class="container">
<div class="row">
<div class="col-md-9">
<div class="all_exthree_blogs">
<div class="row">
<?php
$blogcontent = new WP_Query(array(
'post_type' => 'post',
'posts_per_page' => 6,
'category__not_in' => array( 75 )
));
?>
<?php while($blogcontent->have_posts()) : $blogcontent->the_post(); ?>
<div class="col-md-4">
<div class="single_exthree_blog">
<div class="exthree_box">
<div class="exthree_box_img">
<!-- <img src="img/shutterstock_770159185.jpg" class="img-responsive"> -->
<a href="<?php echo get_permalink() ?>">
<?php if(has_post_thumbnail(get_the_ID())){ ?>
<?php echo get_the_post_thumbnail(get_the_ID(),'medium'); ?>
<?php }else{
$image = vibe_get_option('default_course_avatar');
?>
<img src="<?php echo vibe_sanitizer($image,'url'); ?>" />
<?php
}
$name = get_the_author_meta( 'display_name' );
?>
</a>
</div>
<div class="exthree_box_fortag">
</div>
<div class="boxxx">
<div class="exthree_box_title">
<h4><?php echo get_the_title(); ?></h4>
</div>
<div class="exthree_box_categor_list">
<?php echo get_the_category_list(); ?>
</div>
<div class="exthree_box_desc">
<p><?php echo get_the_excerpt(); ?></p>
</div>
<div class="exthree_box_button">
Continue<img src="http://localhost/gostudent/wp-content/uploads/2020/02/Layer-2.png">
</div>
</div>
</div>
</div>
</div>
<?php endwhile; ?>
<?php echo "helooooooooooooooo"; ?>
<?php $big = 999999999; // need an unlikely integer
$links = paginate_links(array(
'base' => str_replace($big, '%#%', get_pagenum_link($big)),
'format' => '?paged=%#%',
'current' => max(1, get_query_var('paged')),
'total' => $next_the_query->max_num_pages,
"type" => "list"
));
echo $links; ?>
</div>
</div>
</div>
</div>
</div>
</section>
<?php return ob_get_clean();
wp_reset_postdata();
}