I'll be using this section to fill in some content that may have not been covered enough. Other than that, this will be just a reference for other material that will better explain system design than I can.
I would recommend starting with Grokking the System Design Interview eCourse. Worth the money and will fill in a lot of the gaps for a beginner to system design. Use the YouTube channels as supplement and Google's SRE eBook for context to some real life scenario debugging. I highly recommend picking up "Designing Data-Intensive Applications" book, really good read and to the point.
I recommend checking out "Success in Tech" and "Gaurav Sen" on YouTube. I would avoid Tushar Roy's YouTube channel, the quality of system design isn't on par, his channel is only good for DS & Algos.