Aaron,
It has been a super long time! To your topic…

React is popular in the U.S. (job wise), but Vue is popular outside the U.S. Svelte is a compile time framework, where only the runtime is in the production copy, saving on file size. It does not have a router or datastore library yet, so it might take a bit to catch on.

CSS flexbox and grid are the current trends. SASS is still used as a CSS preprocessor of choice, followed by a distant LESS. PostCSS is also talked about.

NPM is the package repository of choice in the U.S. Bower is mostly out. Yarn (Facebook open source) has some traction.

Grunt and gulp are out of favor. Webpack is dominant with some talk of Rollup.

As long as you own your business, you decide what tech you want. No need to chase every shiny new tech. It was supposed to be “the right tool for the right job” but the job environment seems to be “we must use new tech or we cannot be employed or justify or budget.” Unfortunately, this creates a never-ending cycle of tech upgrades at a fast pace. For the money a decent tech worker makes, I wonder if being a lawyer or doctor would be better.