Platform API 429s with low thread count in JMeter

Context:
Running JMeter 5.6.2 from Singapore against /api/v2/architect/flows. Only 10 concurrent threads active. Hitting 429 Too Many Requests instantly despite valid OAuth tokens. Standard GC rate limits seem to apply even at this low volume.

Question:
Does anyone know if there is a strict per-IP throttling for architect endpoints specifically? The docs mention global limits but this feels aggressive for 10 threads. Checking headers now.