How switch theme per domain on single install

I have multiple domains, each for language
I use wpml plugin, set for detect language by domain.

My problem is that i want change the theme by domain.
I try adding this lines in wp-config
switch ( $_SERVER[‘HTTP_HOST’] )
{
case ‘polishdomain.com’:
define( ‘WP_DEFAULT_THEME’, ‘grygratis’ );
define( ‘WP_SITEURL’, ‘https://grygratis.com’ );
define( ‘WP_HOME’, ‘https://grygratis.com’ );
break;
default:
define( ‘WP_DEFAULT_THEME’, ‘blankslate’ );
}
but not work.

How i can change theme dinamically?
Thanks