在Wordpress RSS提要中减少日期

I have to get date in decrement order starting from today in each item of RSS feed. Posts in feed are coming via while loop. And when I try to get date, it only displays one value in each item. This is what I have tried

while ( $the_query->have_posts() ) {
            $the_query->the_post();     
            $post_id = get_the_ID();
            $the_post = get_post($post_id);
            $excerpt = $the_post->post_excerpt;
            $modified = $the_post->post_modified;
            $created = $the_post->post_date;
            $author_id = $the_post->post_author;
            $menu_order  = $the_post->menu_order;
            $post_parent  = $the_post->post_parent;
            $author =   get_the_author_meta('display_name', $author_id );               
            $categories = get_the_category();

            switch ($csrp_pubdate_date_format) {
                case "rfc":
                $today = date('Y-m-d'); 
                for($i=1; $i<=4; $i++)
                {
                   $repeat = strtotime("-1 day",strtotime($today));
                   $today = date('Y-m-d',$repeat);
                   $pub_date =  $today;
                 }
            }//end while loop

I have used loop limit 4 just for testing purpose. It has to be infinite loop.

This is what I get

<item>
  <title>
    <![CDATA[
      The Conundrum of Coffee &#8211; Natural Replacements
    ]]>
  </title>
  <pubDate>2019-08-05</pubDate>
</item>
<item>
  <title>
    <![CDATA[
      The Conundrum of Coffee &#8211; Natural Replacements
    ]]>
  <pubDate>2019-08-05</pubDate>
 </item>

and so on......

This is what I require

<item>
  <title>
    <![CDATA[
      The Conundrum of Coffee &#8211; Natural Replacements
    ]]>
  </title>
  <pubDate>2019-08-09</pubDate>
</item>
<item>
  <title>
    <![CDATA[
      The Conundrum of Coffee &#8211; Natural Replacements
    ]]>
  <pubDate>2019-08-08</pubDate>
 </item>
 <item>
  <title>
    <![CDATA[
      The Conundrum of Coffee &#8211; Natural Replacements
    ]]>
  </title>
  <pubDate>2019-08-07</pubDate>
</item>
<item>
  <title>
    <![CDATA[
      The Conundrum of Coffee &#8211; Natural Replacements
    ]]>
  <pubDate>2019-08-06</pubDate>
 </item>

Can someone please help me to achieve this

Please use in your $the_query 



$args = array(
      'post_type' => 'post',
      'orderby'   => 'date',
      'order' => 'DESC',
      'posts_per_page' => -1
);

$the_query = new WP_Query($args);

while ( $the_query->have_posts() ) {

        $the_query->the_post();     
        $post_id = get_the_ID();
        $the_post = get_post($post_id);
        $excerpt = $the_post->post_excerpt;
        $modified = $the_post->post_modified;
        $created = $the_post->post_date;
        $author_id = $the_post->post_author;
        $menu_order  = $the_post->menu_order;
        $post_parent  = $the_post->post_parent;
        $author =   get_the_author_meta('display_name', $author_id ); 

 }//end while loop

 check with this. Is that you looking for or get_the_category() ?