I need math and CS for my gamedev hobby.

I need to ask this for the CS guys here.

Do I need to have a deep understanding of math and CS topics, like a real CS guy have or is enough I simply review the classes using youtube, be aware X topic exist and is used for Y issue in my game engine or if I want to code a game in C/SDL/OpenGL, so I only need to "Oh, I remember this issue is solved with Y shit I saw on some lecture, so I just need to google and study that Y shit in detail for this project"

So basically I ask:
I need to master CS to code games, or I can simply go by and learn more from doing my own project where I have to actually put the theory into practice to solve any problem I have in my games?