Data Action API 429s during bulk record creation US1

Is there a clean way to handle HTTP 429 Too Many Requests errors when calling /api/v2/integrations/data/actions for bulk data creation? The environment is US1. Using JMeter 5.6 with SDK 2.3.0. The test simulates 50 concurrent users triggering data actions via Architect flows. The error appears after 200 requests per minute. Is this a hard limit on the US1 region?