I'm sure Google can get you tons of learning resources on Web Development. Anyway, I'll suggest the one of the approaches here:
FYI, Frontend development doesn't end at what you see on screen. There's lot going on behind the curtains
MOST IMPORTANT STEP: Pretend for a month or two that there exists no web frameworks out there.
And then, start building static web pages with just HTML, CSS and JS. Like Landing Pages of Website. Spend more and more time on knowing basic fundamentals of HTML, CSS, JS and how all three are interlinked
And then, introduce auto-refresh on change or hot-reloading, bundling in your website through a library like webpack, sounds scary but its not. Just Google -- How to add webpack..., google will get you there.
By now, you'd be serving your website locally hosted on nodejs. You'll realise the magical things that Webpack can do(Checkout their plugin section)
And then, try building a Singe Page Application(SPA) with the same technologies above.
You'll start to realise the pain of developing it..
Now you checkout top three popular frameworks for building SPA -- React, Vue and Angular (not necessarily in order).
You'll now start either appreciating/hating the amount of abstraction web ecosystem has created for developers to make them stay focused on business logic instead of things around the code.
Based on your above opinion, you'd be either continuing building web applications or might not comeback to Web development anytime soon.
P.S. I'm a backend developer too but I love Web development.
Cheeers!