I've typically worked in SRE and platform engineering work and that's where I've gotten exposed to these kinds of Rube Goldberg machines. Make a short list of them when you find them and then use them as a hit list during "cost cutting". Most people don't want to touch these systems because they look big and expansive and generally "work". They're just very poorly optimized.

Dare I say, any time I see a function as a service my brain immediately drifts to inspecting the cost implications of said process.

IT departments, typically, though occasionally there are whole companies that work in "technology" where this type of work can be found.

I said the above as a jest, but seriously, simplification of complex stacks has been a good consulting gig.

Most large companies. There is a stark difference between the distinguished engineers and the tier below them in terms of asking people to stop doing things badly.