How do you start learning this breadth of software engineering? I consider myself good in the python / django space, but where do I start with learning these infrastructure technologies? I find that I use them once or twice periodically, and then don't touch them for so long, so I forget much of what I have learned.
Work at a company that does DevOps well; this is a pretty common deployment pattern because it’s easy to test and gives a lot of flexibility. Many of the things OP is describing are only things you learn in a role with a production support component, which is where you find the tiny details like your health checks were inadequate and driving error rate spikes in certain scenarios without a specific config option, etc. Many of them are things that only pop up when you have some scale to deal with over a period of time, which makes it hard for hobbyists to pick up if they’re not on a team with prod support responsibilities.