I have just completed my online Unity course in which I made 3 3D games and one 1 MOBA. I learned a lot, but I know that there are still lot of things which I don't know? I don't know what Async is, I am still bit confused on Quaternions, I don't know much bout Data Structures and Algorithm, I don't know many Design Patterns, only one Co-Routines or Singletons.

Any experience Game Devs, can please answer it. As I am looking for jobs in Game Dev now, I know I lack experience and speed to make games, but I know about Unity, coding, so can please help?

The things you mention that you are lacking knowledge in are some of the fundamentals of computer programming. Studying those and more will give you a better view on how to program in general, and make you a better programmer inside and outside Unity.

EDIT: If you want to make a living in programming, you will eventually need to know all that.