A lot of us are caught in learning the frameworks and newest techs, but actually we forgot how to code in the language itself.
I recently had a Tech interview and I discovered that I miss a lot of the core concepts of the language, however I know how to run Django Admin site, write SQLite queries for a Django project and deploy an app to Heroku !
My advise, especially to the young who just started their programming journey, learn how to walk first before you run; otherwise you will be very confused and probably would hate to program and might even change your career to be a fisherman instead!
Check out this video, and let me know about other concepts that you would be interested to learn.
Thank You and Happy Learning.