IMO: the cycle largely doesn't matter and can be ignored... hear me out.
Been a web dev since the 90s, on and off, since before Javascript was invented. Twenty years later, it's still largely HTML and CSS, with JS globbed on. Here's the thing: the web, by its very nature, is a mountain of hacks on top of hacks on top of hacks, the result of having way too many cooks in the kitchen with no recipe. It just evolved organically, messily, clobbering different use cases together over time, all through mutating the HTML DOM -- little more than a glorified rich text doc.
Web dev is a craft wide as an ocean, shallow as a puddle. Whatever framework you use or don't use, at the end of the day you're just moving boxes/divs around and highlighting buttons and such. The complexity you see in the toolchain and frameworks is because JS and HTML are so barebones that you can't really do a lot of traditional software stuff with it easily, having to reinvent everything from routing to state management to basic network stuff... not to mention reinvent a backend. So each major tech company or small business or mid-sized SaaS provider sets out to solve some tiny part of it, either to make a name for themselves or to just make some internal workflow easier. The successful ones either see widespread adoption (React) or become part of the ECMAScript specs eventually (fetch, Web Components). And many companies try to invent their own version of an idealized backend, each having some 80% overlap with other major backends, but none that are 100% the best for all uses cases, so now you get to pick and choose from a hundred imperfect solutions rather than one best practice.
But so what? It largely doesn't matter.
Web dev has an incredibly low barrier to entry. Anybody can learn the basics in a few weeks, largely for free, and get a paying job with not much effort. AND it has a pretty low skill ceiling, unless you choose to specialize down a path of (say) DevOps or DB engineer or some backend stack, or start diving into one of the web-adjacent APIs (WASM, WebGL, Canvas). If you just focus on the frontend DOM, it doesn't really matter whether you use vanilla, jQuery, React, Angular, Vue, Svelte... it's all just HTML and JS in the end.
This field has incredible turnover: in frameworks, yes, but also in developers themselves, in managers, in companies, in fashions. As you pointed out, yesterday's "best practices" are today's "mistakes to avoid". Culturally, all of it is ephemeral and so very little of it is mission-critical. Maybe if you're working at an SaaS or IaaS company, you have to plan for 10+ years. But most online businesses just need a fancy catalog or marketing page or knowledge base or whatever, and fundamentally those are just several pages of UIs with a sprinkling of business logic and intertwined states to manage. The challenges are usually in thinking through the architecture and tradeoffs, not necessarily implementing any one framework or another.
At the end of the day, no matter which framework you use, they're still just making and mutating HTML. I can pretty much guarantee that whatever you write is going to be obsolete by the time it hits 1.0, because all the underlying packages and frameworks (and possibly languages and APIs) will have evolved by then. But that's OK. That just means your code can be as throwaway as the ecosystem itself... the standards aren't as high as in proper software engineering. You're just marking up a network-enabled Word document, and if something breaks, it's trivial to fix it and all your users will see the fix the next time they load your site. And two years from now, somebody will get paid to rewrite all of it anyway, using a technology you've never heard of.
While this can be frustrating, it doesn't have to be... if you just accept that the work is by nature ephemeral, that it's all throwaway code, you don't need to be attached to it anymore. Plan the best you can for a couple years out and the rest isn't up to you. No matter what you do, it's going to be redone very soon. You're not building cathedrals, just sand castles.
Alternatively, if you really hate this sort of UI-forward coding, you can also create your own systems of abstraction that architecturally separate business logic from UI code, with a purity of functions that can persist underlying API or framework changes. But then all you really end up doing is creating your own new framework. That's how the web got here in the first place. Everybody keeps trying to abstract away the limitations of the DOM and Javascript.
And if you don't like the new shiny, don't chase the new shiny. PHP and Java work largely the same as they did years ago, and still power large portions of the web. If you don't want to ever touch the constantly-mutating frontend, find a company big enough to let you specialize in backend API design and development so you never have to touch HTML, CSS, or JS. If you like the somewhat shiny, just not the bleeding edge, you can totally do that. Just pick React and roll with it... it's already considered old and lame (meaning mature) by this point, so if you start out knowing you're choosing older tech, it won't matter as much that it's still old 2 years later. For the backend stack, there are also very mature technologies that have relatively stabilized. Who cares what the new kids on the block are doing? If you're not working at multi-million dollar company who own their own data centers and resell their architectures to other companies, nobody is really going to care all that much about your stack, because it's unlikely to be perfect to begin with and it's not going to survive turnover very long. Again, it's all ephemeral, and that's OK. Don't let the perfect be the enemy of the good.
Learning to love the web is learning to love short-lived mediocrity. You're just speed-dating, not marrying a framework. It's all going to be thrown away in a couple years, and nobody will remember or care why you did what you did. That's OK. You won't remember or care either. Just move on then and do something new somewhere else... you're getting paid along the way, and hopefully enjoying yourself enough. Don't worry about the future so much. Nobody else in the web ecosystem does, lol.