Learning the language is one part, but what enables you to make an application are patterns and paradigms: inflating, mvc, mvvm, immutability, functional. These work for all languages, you learn one once, you can apply it everywhere. It just so happens that maybe every 10-20 years a paradigm replaces another. Since i started writing code in the 90s this happened maybe three times. As far as i am concerned all this ever-changing js fatigue talk is complete rubbish. Even the tooling, we're using the same tools that we used 5 years ago (Webpack, Babel, TS, React, Jest, ...). Microsoft/Apple change their platform toolkits quicker than that!

Class lifecycles being replaced by hooks is a radical but much needed change. Learning it isn't complicated and it will enable you to venture on as everything around you sheds the class based component approach. Swiftui, Vue, Svelte and ofc React are just the beginning.