What tech projects actually have interesting work?

I've worked for a number of tech companies (Goog, FB, etc.) and seemingly the majority of the work is braindead CRUD, frontend, or API development hosted on (AWS, GCP, etc).

However there are people out there building the future of technology. Seemingly these jobs are harder to find, so what's a good strategy to find them?

TL;DR I'm sick of programming "business logic" into UI driven apps and I'd like to work on something challenging.