I think the future of components like carousels, tabs, etc is web components.
https://www.webcomponents.org/
In my experience, the only real way to practice CSS is to just use it. Start a bunch of projects. Keep track of any sites you come across that achieve good aesthetics or fun gimmicks. Get an idea for a site, preferably a static site so you can focus more on FE, and just start making these sites. I do this all the time and almost never finish my projects but always have fun making them and definitely improve on my HTML/CSS knowledge each time. Here's some examples of unfinished sites I've played with mostly just to experiment with styling:
https://dontplay.netlify.app/compost
https://ascii.dataviz.gallery/
https://dontplaywithculi.netlify.app/readlater
https://dontplaywithculi.netlify.app/partisanlean
https://culi.page/play/
Lastly, I'd say keep a close eye on accessibility. If you really wanna set yourself apart, the biggest impact you can have in setting yourself apart is learning to use a screen-reader, accounting for all different screen sizes/orientations, etc.