Ask HN: Favorite tools for building an aesthetic UI for a side project/MVP?

I've historically been more of a backend developer and my knack for building good looking UI's is just not there. I've read up on the basics of UI design and tried building out UI's using React + CSS, but it ends up being so time consuming for something that looks mediocre.

What are your favorite UI library or no/low code tool for building a good looking UI for side projects?