<?php

$date_after = strtotime("-1 day");
$date_after = strtotime("-1 week");
$date_after = strtotime("-2 weeks");
$date_after = strtotime("last Monday");
$date_after = strtotime("10 September 2021");

$args = array(
 'post_type' => 'post',
 'date_query' => array(
 'after' => $date_after,
 ),
 'orderby' => 'date',
 'order' => 'DESC',
);
 
$the_query = new WP_Query( $args );