Implement error handler like described here: https://blog.logrocket.com/handling-graphql-errors-like-a-champ-with-unions-and-interfaces/
It's still work in progress. So not production ready!
composer require jbernavaprah/lighthouse-error-handler
php artisan vendor:publish --tag=lighthouse-error-handler
You will se every type new type covered by the default errors from Laravel/Lumen.