Figma For Web Developers

I am new to Figma but I have worked as a developer with designers who use Figma.

One problem that I have experienced is that Figma (like most design tools) throws out very crude HTML/CSS/React. There are a number of problems that arise when developers implement the Figma design.

Based on my experience working with Figma designers, it gives the designers a lot of power to craft a beautiful user interface but it does little to aid the development design/build/test/redesign cycle. Instead, at best, it can be the first step in a waterfall development process.

What are the best practices for including Figma in a design/build cycle? Is there a way to define a theme (CSS) that is maintained across an entire website?