I can tell you from experience, the internal Amazon stack is not cool or inventive.
That said, I've done just fine without that benefit since moving on.
A lot of the internal tooling is due to legacy and inertia. There's 20+ years of history, and so much has been built and continues to be built that it's enormous investment to steer a different direction. Incremental improvements have higher reward ratio. But people do want better a better development experience, especially w.r.t. idiomatic language tooling.
That being said, initiatives are brewing for that "enormous investment".