is using the_posts_navigation() required?

Question

I want to create a theme and get it approved on wordpres.org and want it having number page navigation:

The HTML code should Bootstrap 4's navigation component.

i can accomplish the above with an custom function:

// Numeric Page Navi (built into the theme by default)
function jbst4_page_navi($before = '', $after = '') {
    global $wpdb, $wp_query;
    $request = $wp_query->request;
    $posts_per_page = intval(get_query_var('posts_per_page'));
    $paged = intval(get_query_var('paged'));
    $numposts = $wp_query->found_posts;
    $max_page = $wp_query->max_num_pages;
    if ( $numposts <= $posts_per_page ) { return; }
    if(empty($paged) || $paged == 0) {
        $paged = 1;
    }
    $pages_to_show = 7;
    $pages_to_show_minus_1 = $pages_to_show-1;
    $half_page_start = floor($pages_to_show_minus_1/2);
    $half_page_end = ceil($pages_to_show_minus_1/2);
    $start_page = $paged - $half_page_start;
    if($start_page <= 0) {
        $start_page = 1;
    }
    $end_page = $paged + $half_page_end;
    if(($end_page - $start_page) != $pages_to_show_minus_1) {
        $end_page = $start_page + $pages_to_show_minus_1;
    }
    if($end_page > $max_page) {
        $start_page = $max_page - $pages_to_show_minus_1;
        $end_page = $max_page;
    }
    if($start_page <= 0) {
        $start_page = 1;
    }
    echo $before.'<nav style="text-align:center"><ul class="pagination">'."";
    if ($start_page >= 2 && $pages_to_show < $max_page) {
        $first_page_text = __( "First", 'jbst-4' );
        echo '<li class="page-link"><a href="'.get_pagenum_link().'" title="'.$first_page_text.'">'.$first_page_text.'</a></li>';
    }
    echo '<li class="page-item">';
    previous_posts_link('<span aria-hidden="true">&laquo;</span>
        <span class="sr-only">'. __( 'Previous', 'jbst-4' ) .'</span>');
    echo '</li>';
    for($i = $start_page; $i  <= $end_page; $i++) {
        if($i == $paged) {
            echo '<li class="page-item active"><span class="page-link"> '.$i.' </span></li>';
        } else {
            echo '<li class="page-item"><a class="page-link" href="'.get_pagenum_link($i).'">'.$i.'</a></li>';
        }
    }
    echo '<li class="page-item">';
    next_posts_link('<span aria-hidden="true">&raquo;</span>
        <span class="sr-only">'. __( 'Next', 'jbst-4' ) .'</span>'); 
    echo '</li>';
    if ($end_page < $max_page) {
        $last_page_text = __( "Last", 'jbst-4' );
        echo '<li class="page-item"><a class="page-link" href="'.get_pagenum_link($max_page).'" title="'.$last_page_text.'">'.$last_page_text.'</a></li>';
    }
    echo '</ul></nav>'.$after."";
} /* End page navi */
add_filter('next_posts_link_attributes', 'posts_link_attributes_next');
add_filter('previous_posts_link_attributes', 'posts_link_attributes_previous');
function posts_link_attributes_next() {
    return 'class="page-link" aria-label="' . __( 'Next', 'jbst-4' ) . '"';
}
function posts_link_attributes_previous() {
    return 'class="page-link" aria-label="' . __( 'Previous', 'jbst-4' ) . '"';
} 

Now the theme reviewer tells me "use core the_posts_navigation() for page navigation on your blog index".

the the_posts_navigation() does not give me a numbered pages. I found the the_posts_pagination() functions. This function does not have hooks or filters to change the previous and and next links. I found that i can replace the above function with the following code, which uses get_the_posts_pagination():

<?php
function jbst4_page_navi() {
// Previous/next page navigation.
echo str_replace (
array('"next page-numbers"','"previous page-numbers"'),
array('"next page-numbers" aria-label="' . __( 'Next', 'jbst-4' ) . '"', '"previous page-numbers" aria-label="' . __( 'Previous', 'jbst-4' ) . '"'),
get_the_posts_pagination( array(
  'prev_text'          => '<span aria-hidden="true">&laquo;</span><span class="sr-only">'. __( 'Previous', 'jbst-4' ) .'</span>',
  'next_text'          => '<span class="page-link" aria-hidden="true">&raquo;</span><span class="sr-only">'. __( 'Next', 'jbst-4' ) .'</span>',
  'show_all'           => true,
  'add_args' => array('class' => 'page-item'),
  'before_page_number' => '<span class="page-link">',
  'after_page_number' => '</span>',
  'screen_reader_text' => __('Page navigation', 'jbst-4')
  ) 
)
);
} 
/* End page navi */

The above does not feel as an improvement, i'm also wonder if i do use WordPress features now? So my question is using the_posts_navigation() required in all situations?

Answer 1

The type of pagination you want to use is currently considered 'plugin territory'. Users that download your approved theme must not be forced to use it. They may, for instance, have another system of pagination which they prefer. Therefore a theme must have the barebones pagination of the_posts_navigation() as a standard. It's about ensuring flexibility to your theme's users.

You may try to include your pagination as an option, as @majick suggests, but the formal approach would be to build your pagination into a plugin and recommend your users to install it with your theme.