Architect API 429s during JMeter load test ramp-up

Has anyone figured out why the Architect API endpoints are returning 429 Too Many Requests when JMeter 5.6.2 hits just 50 concurrent threads?

Testing from Asia/Singapore against Genesys Cloud BYOC Edge 24.2. The flow is simple: POST /api/v2/architect/flows to update a basic IVR menu. No complex logic. Just a JSON payload with a greeting and a transfer node.

Error response:

{
 "message": "Rate limit exceeded",
 "status": 429
}

Ramp-up time is 10 seconds. Thread count is 50. Loop count is 1. The docs say the limit is 100 requests per minute for this endpoint, but we are hitting it almost instantly.

Is there a per-tenant limit that is lower for BYOC environments? Or is JMeter sending requests too fast? We tried adding a constant timer of 2000ms between requests, but it still fails.

Any insights on how to bypass this for load testing purposes? We need to simulate high call volumes and updating flows is part of the test scenario.