We use Tokens Studio Figma plugin [1] to export the tokens that the designers defined to a github repo.
We have a few front end projects that consume them - one is sass based, the others are emotion/theme-ui and we have different style dictionary[2] scripts that transform the source tokens for the relevant projects.
Everything was working great until the designers decided the existing tokens were insufficient, and new designers joined who simply chose not to use them (because... reasons).
My point is that tokens work well when there is full alignment between the design and engineering teams. However, it requires extra effort from both sides to consistently "follow the rules".