You are halfway through Python on Sololearn. You will soon reach some nasty chapters here. When that happens, follow some Youtube tutorials. OOP, classes, Itertools might seem impossible, but watch explanations by Corey Schafer for those topics. Then follow through with your course here. Those are, I predict, your next steps. As for mastery? I dont think about that, would feel overwhelmed.
Learn and practice during the course here. Start from something if you want to achieve your goal.
Daily practice makes you master of anything 😎 never ever give up , determinent mind is very important 💥