Wp-admin Redirection loop after moving to subdirectory

try this >>

step 1) on wp-config.php

define('WP_HOME','https://www.my-site.com/my-site.com');
define('WP_SITEURL','https://www.my-site.com');
define('RELOCATE',true);

now, on your /index.php
change this line: require( dirname( FILE ) . ‘/wp-blog-header.php’ );
to

require( dirname( __FILE__ ) . '/my-site.com/wp-blog-header.php' );