Every quickly assembled data hand-off defers a future decision. While it works nobody looks at it; when it breaks nobody knows how it worked.
The minimum we expect on every interface: a documented contract, error handling, retries, alerting and run logs.
Keep an interface catalogue: which systems, which data, at what frequency, owned by whom. It is one table, and it protects you for years.
When you replace a system, that catalogue becomes the most valuable document in the project.