At least going by their own CV, they've mostly written what sounds like small scripting-type programs described in grandiose terms like "data warehouse".
When I talk with people in the space, go to meetups, present my work & toolset, I am usually one of the more advanced, but usually not THE most, people in the conversation / group. I'm not saying I'm some sort of genius, I'm just saying I'm relatively near the leading edge of how to use these tools. I feel like it's true.
I made the jump and pivoted a bit. My first gig was in enterprise applications and then I made the jump to mobile apps that I developed for 5 years.
I got somewhat lucky as the feature my team owned was powered by ML. After gaining credibility on the mobile side I worked with my manager to make the transition to backend. Did backend for about a year and was fortunate with the timing that my team was launching a new product with a model it owned. I got to work closely with ML engineers on it and eventually I became the DRI of the feature along with the model. After 2 more years I came to the realization that ML was moving a bit faster than I could keep up reading white papers about and decided to pivot to ML Ops. This let me leverage my strengths in distributed computing that I developed, be very close to ML without having to study math in my spare time
So humble. Who is he again?