In my part of the industry, a rite of passage is coming up with one's own homegrown data pipeline workflow manager/DAG execution engine.

In the OpenAPI world, the equivalent must be writing one's own OpenAPI spec generator that scans an annotated server codebase, probably bundled with a client codegen tool as well. I know I've written one (mine too was a proper abomination) and it sounds like so have a few others in this thread.