Cannot modify header information in functions.php for wp_list_comments()

In comments.php I use wp_list_comments() and in callback I refrence a function called ‘aseman_list_comments’ that I created in functions.php and I just copy – paste the code that are in [https://developer.wordpress.org/reference/functions/wp_list_comments/]

function aseman_list_comments($comment, $args, $depth) {
    if ( 'div' === $args['style'] ) {
        $tag       = 'div';
        $add_below = 'comment';
    } else {
        $tag       = 'li';
        $add_below = 'div-comment';
    }?>
    <<?php echo $tag; ?> <?php comment_class( empty( $args['has_children'] ) ? '' : 'parent' ); ?> id="comment-<?php comment_ID() ?>"><?php 
    if ( 'div' != $args['style'] ) { ?>
        <div id="div-comment-<?php comment_ID() ?>" class="comment-body"><?php
    } ?>
        <div class="comment-author vcard"><?php 
            if ( $args['avatar_size'] != 0 ) {
                echo get_avatar( $comment, $args['avatar_size'] ); 
            } 
            printf( __( '<cite class="fn">%s</cite> <span class="says">says:</span>' ), get_comment_author_link() ); ?>
        </div><?php 
        if ( $comment->comment_approved == '0' ) { ?>
            <em class="comment-awaiting-moderation"><?php _e( 'Your comment is awaiting moderation.' ); ?></em><br/><?php 
        } ?>
        <div class="comment-meta commentmetadata">
            <a href="<?php echo htmlspecialchars( get_comment_link( $comment->comment_ID ) ); ?>"><?php
                /* translators: 1: date, 2: time */
                printf( 
                    __('%1$s at %2$s'), 
                    get_comment_date(),  
                    get_comment_time() 
                ); ?>
            </a><?php 
            edit_comment_link( __( '(Edit)' ), '  ', '' ); ?>
        </div>

        <?php comment_text(); ?>

        <div class="reply"><?php 
                comment_reply_link( 
                    array_merge( 
                        $args, 
                        array( 
                            'add_below' => $add_below, 
                            'depth'     => $depth, 
                            'max_depth' => $args['max_depth'] 
                        ) 
                    ) 
                ); ?>
        </div><?php 
    if ( 'div' != $args['style'] ) : ?>
        </div><?php 
    endif;
}

I just change function name 😉

I works great on comment section but in admin dashboard I get some errors:

“Cannot modify header information – headers already sent by….. “

I know what the problem is for:

<<?php echo $tag; ?> 

is not closed before the final }.
if I use

</<?= $tag; ?>> 

before the final } errors gone but commnet structure is mess up

How can I fix this problem?