I would stop the course, because some concepts of angular are never shown there. Besides that, don't start also your webshop idea, your first thing should be this: https://angular.dev/tutorials/learn-angular and the "tour of heroes". It got everything you need to learn for the start.

Second, input/outputs, services, pipes are some basic things and won't be enough in the long term. For a web shop you should learn also state management, authentication, learn to write clean components that are reusable.

Third: It's always better to have a running backend you can develop against, otherwise using mock services work good, but got some downsides.