Xdebug not working over Drush
From https://github.com/drush-ops/drush-launcher#xdebug-compatibility:


  Drush Launcher, like Composer automatically disables Xdebug by default. This improves performance substantially. You may override this feature by setting an environment variable. DRUSH_ALLOW_XDEBUG=1 drush [command]


So to make Xdebug reach the rest of your code, add DRUSH_ALLOW_XDEBUG=1 to the environment variables in front of your command.