Your while
loop means, “Every time I have one post, output the following code.” Since you have 5 divs inside the while
loop, you are getting 5 copies for each post. So, change your while { }
code to this, which will output just 1 div for every post:
while($blogposts->have_posts()) {
$blogposts->the_post(); ?>
<div class="col-md-6">
<a href="https://wordpress.stackexchange.com/questions/359025/<?php the_permalink(); ?>
<div class="card border-0">
<div class="card-picture">
<img class="card-img" src="<?php echo get_the_post_thumbnail_url(get_the_ID()); ?>" alt="Card image">
<div class="card-img-overlay d-flex flex-column">
<h5 class="card-title font-weight-bold"><?php the_title(); ?></h5>
<div class="mt-auto"> Miika - <i class="fas fa-clock"></i> 16.2.2020 - Oppaat</div>
</div>
</div>
</div>
</a>
</div>
<?php }