"Plus, IME most companies carry so much cultural context that being exposed to it for exactly 1 ticket + not having inside people to ask questions means this will be an uphill battle."

I'm curious as to how you make this work when I'd imagine even a simple ticket for anywhere I've worked would go something like this: "first learn our monorepo, then learn how all the internal testing tooling works, and oops your PR is going to touch our in-house/NIH'd migration system. Also you can't just rename this db column, let me explain our db replication strategy (which you can't touch or observe since no way would a non-employee have any of our AWS access, even for dev). oh and Jim (haha good ole jim, he wrote like 40% of the code and then got fired after 2 years because he told the CTO to go fuck himself) wrote that code in a rush in the before times so it's creaky, try not to ever touch or look at it, so work around it in the app code even if you might otherwise want to change it" and so on and so on.

(I also find learning all this stuff - the NIH systems, the stack, who the Jim is this time around and what code he wrote, etc - is like 85% of the part of spinning up at a new company and it takes like 6 months of fireside campfire stories to pick up enough of the lore)

It sounds like a shop like this would basically mean devs are eternally in that "doesn't know about Jim's code yet" stage.