I think it is a reasonable expectation to require a certain baseline of expertise, considering the first thing the poster admitted to was: "I'm a data engineer

I think it is a reasonable expectation to require a certain baseline of expertise, considering the first thing the poster admitted to was: "I'm a data engineer for a startup that's trying to hire its first data scientist." Much like how the early hires at Twitter were not deeply experienced in high availability work -- segregating the architecture of a predominantly RoR code base to be resilient at scale, which lead to countless "fail whale" outages, before they eventually landed someone who helped them re-think their architecture to use RoR for what it's good at while introducing the JVM and other languages to handle other aspects of their workload.