My question is learning about design ideas like having Redis keeping a list of "work to be done" and such. Using modern tools to combat 'modern' problems. Is it just something you figure out after knowing the fundamentals (i.e. when you can identify a problem you know what the solution needs to be)?
If it sounds mysterious, think of it this way: Imagine you were thrown into a room with a computer, internet, and endless food, and the only way out of the room was to solve this problem. I bet you'd figure it out within a week or two, or a couple months max. (If only to go have a shower.)
One thing to watch out for: Solving modern problems can be pretty unsatisfying. Before you experience what life is like at a modern company, you tend to think of them as functional, orderly, and planned. Real companies are almost universally dysfunctional, disorderly, and haphazard. It's very rare that a plan is conceived, followed, and deployed without growing some warts and throwing in some hacks to get it done.
So I think you should enjoy this time, where you're free to think of thought-problems like "What's the most correct and extensible way to solve this problem?" instead of being forced to solve them on a time crunch.