Not compatible with WP constants

Your plugin ignores any WP constants which might be set to change the wp-content folder, like which is used in https://roots.io/bedrock/.

See a list of WP constants here.

When I use the aforementioned setup, your plugin tries to retrieve assets from
/var/www/html/web/app/http://subdomain.127.0.0.1.nip.io/app/themes/boo-child/style.less.

So that won’t work.