What would be the best path to learn front end development so I can transition to full stack? I know it's a field that tends to change constantly, so I'd hopefully want updated resources.
I must say that my goal is for my skills to be marketable, so the more mainstream the approach the better.
My bet was to "learn" about the Web platform and not a specific framework. However, to build a Single Page App, you need a library. At that time, I fell in love with Polymer as a minimal library to create a Single Page App. Nowadays, this is replaced by Lit (lit.dev). The library is minimal and aims to use the Web platform as much as possible. I suggest giving it a look.
Besides, when I say "learn", I mean developing a project or something from scratch. You will most probably end up using TypeScript, Jest, Rollup/Webpack and Lit ;)
Good luck!