In early 2019, I joined JPMorgan Chase & Co. and I made a conscious switch from being a front-end engineer to a full-stack engineer focusing predominantly on the back-end. It was a tough endeavour and to get productive, I needed to improve my skillset in a bunch of new technologies.
I decided to spend some time doing courses on a few massive-open-online-course platforms like Pluralsight and Coursera and took down notes. Check them out.