> This is a good question, but I’m not sure if there’s a good answer.

I think you've actually given a great answer here. This is essentially what I did in grad school as well and found it really helpful. I never thought to continue doing this in fields that piqued my interest. Thanks for the suggestion!

While we're on the topic, here's the advanced distributed systems reading list from UIUC:

https://go.cs.illinois.edu/CS525SP21ReadingList

I took the class a number of years ago, but found it super interesting.