Need Help to make a logic for editing posts in Frontend

I have an issue, I’m creating classified website,
so I have a login and a registration form and users can post their own adverts.

They have account page where they can see their posted adverts, I’m using WP_Query.
And I want to add possibility to edit these posts.

I’m using wp_update_post() and everything is working except I can’t understand how can I make post ID be dynamic.

Imagine you go to your account page where you can see all adverts posted by you, and you have button "Edit advert", you click on it and go to new page with simple form where you can edit your advert.

Here is my code for my form page template:

<?php 
/*
Template Name: Edit Post
*/
get_header(); ?>
<main role="main">
    <?php if(is_user_logged_in()) { ?>
        <h3>Edit Post</h3>
        <form id="edit_form" method="post">
            <input type="hidden" name="iseditpost" value="1" />

            <label for="edit_title">Title</label>
            <input type="text" name="edit_title" />

            <label for="edit_content">Sample Content</label>
            <textarea rows="8" name="edit_content"></textarea>

            <input type="submit" value="SUBMIT" name="submitpost" />
        </form>
    <?php } else { ?>
    <h3>You must be logged in</h3>
    <?php } ?>
</main>
<?php get_footer(); ?>

Here my code for editing post:

if(is_user_logged_in()) {

    if(isset($_POST['iseditpost'])) {

        $post_title = $_POST['edit_title'];
        $post_content = $_POST['edit_content'];

        $my_post = array();
        $my_post['ID'] = 350;
        $my_post['post_title'] = $post_title;
        $my_post['post_content'] = $post_content;

        wp_update_post( $my_post );

    }
}

So as you can see here $my_post['ID'] = 350;, I need 350 to be dynamic, so when user click on button "Edit advert" and redirect to page template with form, post ID must be valid for this advert.

And I can’t find out how to make it.

Sorry for my explanation, if you have any question I will be very glad to try to explain better.
Thanks in advance!

P.S. Don’t look at my validation and sanitization, I will do it later!

<ul>
    <?php foreach( $users_posts as $users_post ) : ?>
        <li>
            <span><?php echo esc_html( $users_post->post_title ); ?></span>
            <a class="button" href="/edit?id=<?php echo esc_attr( $users_post->ID ); ?>">Edit</a>
        </li>
    <?php endforeach; ?> 
</ul>

<?php 
$post_id = ( ! empty( $_GET['id'] ) && is_numeric( $_GET['id'] ) ) ? absint( $_GET['id'] ) : 0;
$post_to_edit = $post_id ? get_post( $post_id ) : false;
if ( current_user_can( 'edit_post', $post_id ) && $post_to_edit ) : ?>
    <form id="edit_form" method="post">
        <label>
            <span>Post title</span><br>
            <input type="text" name="post_title" value="<?php echo esc_attr( $post_to_edit->post_title ); ?>">
        </label>
        <!-- more form fields -->
        <input type="hidden" name="id" value="<?php echo esc_attr( $post_id ); ?>">
        <!-- nonce field -->
        <!-- submit -->
    </form>
<?php else : ?>
    <p>Nothing to see here</p>
<?php endif; ?>

add_action( 'template_redirect', function(){
    $post_id = ( ! empty( $_GET['id'] ) && is_numeric( $_GET['id'] ) ) ? absint( $_GET['id'] ) : 0;
    $post_to_edit = $post_id ? get_post( $post_id ) : false;
    if ( ! current_user_can( 'edit_post', $post_id ) || ! $post_to_edit ) {
        nocache_headers();
        wp_safe_redirect( home_url( '/' ) );
        exit;
    }
});