Analytics API 429s during load test

Can anyone clarify the rate limits for the analytics v2 call summary endpoints?

Running JMeter 5.6 in US1 to pull historical data for 10k calls. Getting 429 Too Many Requests after 50 requests per second.

The docs mention 100 req/sec but it seems lower in practice. Is there a specific header needed for batching?

Need to hit 200 req/sec for the test report.