Plugin shortcodes dont work

I am in the process of creating a new site and havent used any plugins to date but needed a grid gallery one and this is where I found my issue. I have put the shortcode on the page, and thought I had a conflict but it seems its my php and with that the php from wordpress and how I have used it, I think anyway.

I have created a new template and this template is used on every page, and the code is below, and so I believe the shortcodes dont work because of the php that allows the content of each page to display on the page.

<?php /* Template Name: MonnowTemplate */ ?> 
   
<?php
$backgroundImg = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'full' );
get_header();
?>
<button class="hamburger hamburger--arrow is-active" type="button" id="menu-toggle-mobile">
<span class="hamburger-box">
<span class="hamburger-inner"></span>
</span>
</button>

<div id="overlay" onclick="off()">
<img id="overlayImage" src="https://www.accend4web.co.uk/Monnow/wp-content/themes/twentytwenty-child/images/M-Logo.png" />
</div>
<div class="d-flex toggled header-wrap" id="wrapper" style="background: url('<?php echo $backgroundImg[0]; ?>') no-repeat; ">

<!-- Sidebar -->
<div class="bg-light border-right" id="sidebar-wrapper">
<div class="sidebar-heading" style="text-align:center"></div>
<br/>
<nav class="navbar navbar-expand-lg navbar-light bg-light border-bottom" style="position:relative; float:right;">
<button class="hamburger hamburger--arrow" type="button" id="menu-toggle">
<span class="hamburger-box">
<span class="hamburger-inner"></span>
</span>
</button>
</nav>
 
<div id="navItemsSidebar">
<div class="list-group list-group-flush hiddenAway" id="monnow-menu">
<?php
if ( has_nav_menu( 'primary' ) ) {
wp_nav_menu(
array(
'container'  => '',
'items_wrap' => '%3$s',
'theme_location' => 'primary',
)
);
}
?>
</div>
</div>
</div>
<!-- /#sidebar-wrapper -->

<!-- Page Content -->
<div id="page-content-wrapper">
<div class="container-fluid">
<?php
if ( have_posts() ) {
while ( have_posts() ) {
the_post();
get_template_part( 'template-parts/content', get_post_type() );
}
}
?>
<?php get_template_part( 'template-parts/pagination' ); ?>
</div>
</div>
<!-- /#page-content-wrapper -->

</div>

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