WordPress replace a tag with span if href and text same

function theme_slug_filter_the_content( $content ) {
     $content = preg_replace_callback(
        '/<a\s+href="([^"]+)"[^>]*>([^<]+)<\/a>/i',
        function($matches) {
            if ($matches[1] === $matches[2]) {
                return '<span class="link_fix" href="'.$matches[2].'">' . $matches[2] . '</span>';
            } else {
                return $matches[0]; // Return unchanged anchor tag
            }
        },
        $content
    );
 return $content;
}
add_filter( 'the_content', 'theme_slug_filter_the_content', 999999);