Write Worlds Your Readers Won't Forgetby Stant Litore I'm generally skeptical of any book series on writing—most tend to beat about the bush. However, "Characters" and "Worlds" are short, sweet, and to the point. Check out the entire series here.
Exercises in Styleby Raymond Queneau In which an anecdote is retold in 99 literary styles. The only book on the list that is not technically on writing, but it can teach you more than some books that are.
About Writingby Samuel R. Delany Not to be confused with King's "On Writing." This one is much more advanced and insightful. To get a taste, check out About 5,750 Words from Delany's "The Jewel-Hinged Jaw."
Unity Disclaimer: I've never used Unity—only worked in Unreal. You might want to learn one or the other or both. Some studios use in-house engines, but between Unreal and Unity you'll be fine. To get started with Unity, check out its documentation and official tutorials.
Perforce/Git/etc. No matter the engine, you need to be familiar with version control.
Miro Digital whiteboard for real-time visual collaboration. You either love it, or love it.
Jira Issue management tool essential to agile development.
Confluence Wiki platform to keep lore bibles and design documents organized.
Honorable mentions, which I haven't used professionally but had a great time dabbling in both: Inky
Cross-disciplinary collaboration is key in game development. Knowledge in different disciplines can not only help you build rapport with your colleagues, but also make you a more well-rounded designer and writer. Some good resources in other design areas:
Numbeo When comparing salaries in different countries and/or looking to relocate, always consider the cost of living. This is the best site to calculate it.
Discord Communities
where aspiring and working game narrative people congregate.