How to add a function from a plugin to a button?

I have a simple site with just a button, and also I’m developing a plugin, what I want to do is that when I click that button the plugin will create a post. But so far, I’ve been having trouble connecting them both.

I’ve tried something like this with a custom HTML block:

<button id="create-post-button">Create New Post</button>

<script>
jQuery(document).ready(function($) {
    $('#create-post-button').click(function() {
        $.ajax({
            url: '<?php echo admin_url('admin-ajax.php'); ?>',
            type: 'POST',
            data: {
                action: 'createPost'
            },
            success: function(response) {
                alert(response);
            }
        });
    });
});
</script>

And my plugin php file looks like this:

<?php
/*
 * Plugin Name: ReachDog WordPress Plugin
 * Description: Test Plugin for ReachDog in WordPress
 */


defined ('ABSPATH') OR die("You shouldn't be here!");

class ReachDogPlugin {
	function __construct(){
		add_action('wp_ajax_createPost', 'createPost');
		add_action('wp_ajax_nopriv_createPost', 'createPost');
	}
	
	function createPost(){
		// Set the post data
		$new_post = array(
			'post_title' => 'ReachDog Post Title 1.2',
			'post_content' => 'One day this is going to be an actual nice plugin, for now this is all you get, Junior quality kind of code.',
			'post_status' => 'publish',
			'post_author' => 1, // The ID of the user who is creating the post
			'post_category' => array(2, 3) // An array of category IDs to assign to the post
		);

		// Insert the post into the database
		$new_post_id = wp_insert_post($new_post);

		// Check if the post was successfully inserted
		if ($new_post_id) {
			echo "New post created with ID: " . $new_post_id;
		} else {
			echo "Error creating new post.";
		}

		wp_die();
	}
}

if(class_exists('ReachDogPlugin')){
	$reachDogPlugin = new ReachDogPlugin('ReachDod Plugin Initialized!');	
}

But still, when I click the button nothing happens, I’m not sure what I’m doing wrong to connect the button to my plugin.