Designers who are looking for a cool and skillful visualizer will not care if you have made a render of your design or a design from my course. It is important for them to see the presentation and quality of your work.
Why everyone makes the same design: I tell you the nuances that will help make the render juicy and tasty, and show it by a concrete example. There is a concrete example and specific tools for it. And also this design gives showiness to the render.
If you immediately apply knowledge on another project, it may have a bad effect on their digestibility, and also this project will have a different design, and it may not cause a potential customer to resonate, and then the result will be worse.
You need to do all this together with me, understand and feel it on a concrete example. Get the result and start using it as a portfolio.
And after that you can come up with your own concept and re-apply all this knowledge on it, already based on its specific features