Waterfall design is about controlled fallback, not blind retries. Each provider should have a defined role, a confidence threshold, and a clear reason to continue or stop.
Order providers by expected quality and cost for your data profile. Expensive calls should happen only when low-cost sources cannot satisfy required fields.
Add checkpoints after each stage to record what changed. These snapshots make debugging straightforward and allow teams to tune provider order with evidence.
Over time, the best pipeline is the one you can explain in one page and improve in one week.