Less power but more powerful? How?
I see developers who are overly focused on JavaScript (or its overly cautious cousin, TypeScript) in order to level up their web development game. But that's not where the real power of the web platform is.
The holistic approach
Web development is unique in that it, by default, requires three different languages to work. On the web, JavaScript does not exist in isolation from the other two pieces of technology we use: HTML and CSS. Web pages (including applications) are a combination of all three languages.
You can't just focus on one of them if you want to level up. You have to cultivate a holistic approach and learn how to leverage the simplest mix of the three that gets the job done. When executed correctly, you are removing moving parts and reducing the opportunities for bugs.
Remember that HTML and CSS are purely declarative languages. They have virtually no moving parts — that is, the moving parts are hidden in the browser and you can't mess with them. In most cases, elimination of moving parts means less things to break. Moving as much of your functionality into the purely declarative layers will — in theory — yield a more robust solution.
This school of thought is called "the rule of least power", and apparently Tim Berners-Lee thought it was important enough to dedicate a whole page on W3C to the topic.
Rule of least power in practice
The rule of least power is one of those things that you just have to discover over time. The rule itself is simple enough, but the practical application of the rule requires muscle memory and broad knowledge of the options we have at our disposal.
These options also tend to widen as the capability of the platform increases. For instance, with the introduction of scroll snapping in CSS, it has become possible to implement carousels without using a single line of JavaScript.
To get some intuition about how to do this, try to think in the direction of "pure CSS" implementation of whatever UI you are working on, or even a "pure HTML" one. Naturally, not all UI can be built that way, but trying to go to the extreme will show you where exactly you're missing JavaScript.
