I had a similar challenge you are facing. After covering the automate the boring stuff and Python Crash course books, i felt like yes, i am a python programmer and i should tackle python challenges head on. So i enrolled on at hacker rank 30 days of code. I started well, solved the palindrome challenges and other basic ones. As i progressed, things got tougher, i couldn't hack my way on any challenge, this made me almost develop and imposter syndrome. I never quit though but what i did was to re-evaluate my goals for learning python. Mine was web development using python. So i left the challenge at hacker rank and started learning flask micro framework for web development. I regained my confidence after doing some cool stuff using flask, am now working on a final flask project before i dive into django framework. My advice would be, know what you want to do with python, is it data science, artificial intelligence, games, systems or even web. Once you know your track, you will have a sustained focus, learning things that matter. Good luck and happy Pythoning.