How to insert text between the page numbers? [closed]

Inside my article I use the tag <!--nextpage-->. Now how to insert text between the page numbers. In HTML it should look like this:

<div class="postlink">
<p style="text-align: center;">my test 1</p>

<a rel="nofollow" href="https://domen.com/linkpost/2/"> 2 </a>
<a rel="nofollow" href="https://domen.com/linkpost/3/"> 3 </a>
<a rel="nofollow" href="https://domen.com/linkpost/4/"> 4 </a>
<a rel="nofollow" href="https://domen.com/linkpost/5/"> 5</a>

<p style="text-align: center;">my text 2</p>

<a rel="nofollow" href="https://domen.com/linkpost/6/"> 6 </a>
<a rel="nofollow" href="https://domen.com/linkpost/7/"> 7 </a>
<a rel="nofollow" href="https://domen.com/linkpost/8/"> 8 </a>

<p style="text-align: center;">my text 3</p>

<a rel="nofollow" href="https://domen.com/linkpost/9/"> 9 /a>
<a rel="nofollow" href="https://domen.com/linkpost/10/"> 10</a>
<a rel="nofollow" href="https://domen.com/linkpost/11/"> 11 </a>
</div>

If you’re using wp_link_pages() with 'next_or_number' set to 'number' (or not set at all, it’s the default), which you presumably are, then you can use the wp_link_pages_link filter.

wp_link_pages_link lets you filter the HTML for each individual page link that’s output. The 2nd argument, $i, gives you the page number. You can use this to conditionally output HTML before or after the link depending on the current page number.

For example, if I wanted to output a <br> tag after the second link, I would do this:

function wpse_296614_page_link( $link, $i ) {
    if ( $i === 2 ) {
        $link = $link . '<br>';
    }

    return $link;
}
add_filter( 'wp_link_pages_link', 'wpse_296614_page_link', 10, 2 );