I say, start with the basics. Serve a few static HTML pages and use plain JS to make them a little interactive to find out how DOM manipulation and event triggers/listeners work. Try styling the pages with plain CSS to get a sense of how to use flexbox. I think if you dive straight into something like React, you'll end up being inundated with tooling.
Not bothering!
That’s interesting. A lot of back end engineers I know have an almost allergic reaction to anything to do with front end development.