you raise a very important point: the tooling around CSS is nothing like we have everywhere else. you can get class completion with Tailwind or CSS Modules (which I prefer), but even basic stuff like CSS Variables or SASS mixins are a black hole
I don’t know what tooling you use, but IntelliJ does all that for me, including autocomplete for variables, HTML elements in HTML files or components, and so on.
If you use the inspections, it can also make dead code removal really easy.
What I'd really like is more intellisense for css so I could take a css file and get sensible code complete and class suggestions for elements.