Tag keywords hyper link creation

Hello,

I am managing one website. When I create a post i will enter tag keywords in tag section of post in WordPress. When i save the post I need php/javascript function to get the current post’s tags and create hyperlinks in the content and should save it to database. when a normal user access the post he should see the hyperlinks for the tags of that post. I am using generatepress child theme. I have searched internet, or other platforms But i did not get the code. tag hyperlink creation only happens at admin side when a post saved to database. It should not impact the performance when a normal user access the website and reading the posts.

The below code I tried it always gives 500 internal server error. Can anyone suggest whats wrong in this code and rectify?

<?php {

function save_post_content_with_hyperlinks( $post_id, $post_content ) {
// Check if the user is an admin.
if ( ! current_user_can( 'manage_options' ) ) {
    return;
}

// Check if the post ID is null.
if ( is_null( $post_id ) ) {
    return;
}

// Check if the post content is null.
if ( is_null( $post_content ) ) {
    return;
}

// Get the post tags.
$post_tags = get_the_tags( $post_id );

// Check if the post tags are null.
if ( is_null( $post_tags ) ) {
    return;
}

// Create an array of hyperlinked tag keywords.
$hyperlinked_tags = array();
foreach ( $post_tags as $tag ) {

    // Check if the tag is null.
    if ( is_null( $tag ) ) {
        continue;
    }

    $hyperlinked_tag = null;
    if ( ! is_null( $tag ) ) {
        $hyperlinked_tag = '<a href="' . get_tag_link( $tag->term_id ) . '">' . $tag->name . '</a>';
    }
    $hyperlinked_tags[] = $hyperlinked_tag;
}

// Replace the tag keywords with hyperlinked tag keywords in the post content.
$post_content = str_replace( $post_tags, $hyperlinked_tags, $post_content );

// Update the post content in the database.
wp_update_post( array(
    'ID'           => $post_id,
    'post_content' => $post_content,
) );

// Return the post content with hyperlinks.
return $post_content;
}
add_filter( 'save_post', 'create_hyperlinks_for_tag_keywords', 10, 2 );