ECE Engineer looking for career advice

Hello,
So it has been 2 days since I graduated from Electronics and Communication Engineering. But to be honest things are extremely depressing, I'm a guy who loves science so much, I used to hate college system, I hardly graduated with 3.1/4 GPA due to the wrong system we should follow. I am good in learning, my graduation project was BCI using FSO channel. but I feel a lot of courses we were supposed to understand is lost. some professors were really so bad so we had to memorize everything just to pass. they treated us as if we have ph.D in Engineering and assumed we can understand their mysterious talk.
I want to know how to fill this gap? I want to know how can I cover everything we study in college and even in a better way. any specific youtube channels? courses sites? and what do you advise about work? cuz I hear that most probably when u work you just "use" stuff but u won't be a developer engineer. I want to be good in designing using matlab and circuits and communication techniques .
I hope someone helps me cuz I am craving for science and knowledge and I don't know where and how to start.
Thanks in advance