A big chunk of those are only used during development and compilation (like `6to5` and `Babel` and all the `@types` libs). They are not (or at least should not be) included in the final, downloadable product.
Most likely one of the dependencies required a certain version and did not include the caret (certain version or higher), and another dependency did the same thing with a different version, and so on.
Slack is trash - for this and many other reasons. Social media and engineered engagement has no reason to be in the workplace. They're profiting from dark patterns.
