Help with SQL to limit comments by meta

I’m building a private comments plugin, whereby comments can only be viewed by the comment author and the commenter. I’m doing this by making the comment_type = private, recording the sender and recipient as metadata.

I’m limiting the displayed results using code found
here

The code below let’s me limit results by one metakey => metavalue, but not two. Can anyone help me adapt it?

I.e. I want to retrieve all comments WHERE ( (metakey = ‘sender’ AND metavalue = ‘$current_user’) OR (metakey = ‘recipient’ AND metavalue = ‘$current_user’) )

/**
 * Limits displayed comments on front and backend to just those with the
 * specified meta key/value pair.
 *
 * @param array $pieces
 * @param WP_Comment_Query $query
 * @return array
 */
add_action('comments_clauses', function(array $pieces, WP_Comment_Query $query) {
    global $wpdb;

    $meta_query = new WP_Meta_Query();
    $meta_query->parse_query_vars([
        'meta_key' => 'recipient',
        'meta_value' => $current_user,
        ]);

    if ( !empty($meta_query->queries) )
    {
        $meta_query_clauses = $meta_query->get_sql( 'comment', $wpdb->comments, 'comment_ID', $query );

        if ( !empty($meta_query_clauses) )
        {
            $pieces['join'] .= $meta_query_clauses['join'];

            if ( $pieces['where'] )
                $pieces['where'] .= ' AND ';
            // Strip leading 'AND'.
            $pieces['where'] .= preg_replace( '/^\s*AND\s*/', '', $meta_query_clauses['where'] );

            if ( !$query->query_vars['count'] )
            {
                $pieces['groupby'] = "{$wpdb->comments}.comment_ID";
            }
        }
    }

    return $pieces;
}, 10, 2);