I agree, I work on an "airgapped" BYOC system as well, that runs on data lake providers mostly, and it's a bit of a nightmare because each customer has their own labyrinthine network setup, their own way of ingesting data (as much as we try to be prescriptive, some of them just insist on doing it their way), vastly differing scales and shapes, and sometimes their own secure communication tooling to even read the emails describing the problems they have. It's basically shrinkwrap software.

We're moving away from it as much as possible lately for all but the biggest customers with the strongest isolation needs.

I am also struggling with coworkers thinking they can cowboy code some LLM written features into these codebases recently, not understanding the level of human verified testing that needs to catch all the manifold edge cases and weird decisions in their usage. An update that causes crashes is much harder to catch when you can't do slick blue-green deploys and similar things to roll out updates.