[nothingeasy]

1) Networking: While I don't plan to do much home networking, knowing fundamentals would be helpful to my day to day. So I'm going to go through Computer Networking: A Top Down Approach (https://gaia.cs.umass.edu/kurose_ross/index.php) and augment it with CS 144 (https://www.scs.stanford.edu/10au-cs144/).

2) SQL: As another user mentioned, while I am primarily a FE, there are times when I need to work on the backend and having a shaky understanding of SQL can be a major stumbling block. I might start a bookclub in my city or at work just to ensure I'm consistent with learning.

3) C++/Rust: Will probably do a basic project and may hire a code mentor to do some code reviews/guidance.

[RockyMcNuts]

Online practice on Stratascratch is good for SQL (SQLbolt and SQLzoo for the basics) ... Pavlo, Widom, Date for CS of database systems.

[ArchmagosAkhaya]

What platform do you use to hire code mentors? I would be grateful if you shared any past experiences with them.