Outbound Campaign POST 429s at 5 RPS

Trying to understand why POST /api/v2/outbound/campaigns returns 429 immediately after hitting 5 requests per second. Running JMeter 5.6.2 against Genesys Cloud BYOC Edge 24.1.0 in Asia/Singapore. The Outbound API docs mention rate limits but don’t specify the exact threshold for campaign creation. Is this a hard limit for new environments?