Lazy loading can be achieved by just pointing the router to the module using the special string syntax*, or the new ESNext import syntax*. No need to import anything from the module-to-be-lazy-loaded, including routes.
For example take a look at his repo: personal-routing.module gets imported into personal.module and the main routing module only points to the personal.module

*See Route Configurations use Dynamic Imports in this article from Angular core team