As someone who hasn't done much web development in the last 10 years, it is mind-boggling how much you need to know in order to be a full-stack engineer these days. I tried to start a project a few months ago and just trying to decide on a technology was difficult. Npm, Gulp, Grunt, Webpack, React vs Vue vs Angular...I don't even know what half of these tools even do, why they're needed, not to mention the learning curve to get up to speed.
I got really jaded along with a few other things and let my skills stagnate for a few years and now I'm looking at jobs and I'm unqualified for all the half decent ones. I'm personally trying to switch out of development, but I kinda wish I had made an effort to at least understand some of the new(ish) stucc
I feel your pain. This is one of the few industries that doesn't value experience. Unless you're spending all your time learning new technologies, it's really easy to become irrelevant.
And there are like 20+ popular javascript (or Typescript, CoffeeScript, Dart) frontend frameworks to choose from (Vuejs, React, Angular, ...) several "native" solutions if you also want Mobile apps (NativeScript, ReactNative or even Flutter if HTML is not looking good enough) and there are like 10+ languages to choose for the backend development. And don't forget proper state management (Redux, RxJS, NgRx or Vuex). So if you plan to make a simple admin webpage you can either quickly write 50-line code in PHP or Python or some other lang. Or you can spend months learning TypeScript, webdev tools, js frameworks, Golang (+dependency management), java (+maven, gradle or some other tools from hell) and spend half a year on it. I have spent so much time learnig all that frontend and backend sh*t to find out "yeah it's nice and interactive but next time I should use HTML+CSS+AJAX)". Webapps are for teams of people. Frontend team and backend team. You need like 10 people to make modern SPAs roperly, also with all the proper CSP, headers and caching settings.
Try a minimal set up with create react app with typescript and react testing library. Go through the react and typescript docs. Try Formik for easier forms next. Axios for HTTP requests. You can then venture into client side routing with React Router and finally may be Redux for complex state management.