You don’t need to make something unique, if your goal is to learn.
The best thing you can do is to build something that solves a problem for you, or to build something that already exists that you know well.
As for money, given that companies seem to love layoffs lately, I would say that higher salaries only matter if you are employed. It’s an employers market right now, and a lot of people are really struggling to find work again, even from large companies like Amazon and Google.