Architect Flow Timeout on High Concurrency in AP-SG

Quick question about handling timeout errors in Architect flows when pushing concurrent call volumes. I am running a basic load test using JMeter 5.6.2 against our Genesys Cloud instance in the Asia Pacific (Singapore) region. The goal is to establish 100 concurrent inbound calls to a single Architect flow that simply plays a greeting and then disconnects. When I ramp up to 50 concurrent threads, everything works fine. However, at 80+ threads, I start seeing 408 Request Timeout errors in the JMeter logs and the calls drop before the greeting finishes. The flow itself is very simple, just a Play Prompt block followed by a Hang Up block. I have checked the SIP trunk configuration and it looks standard for BYOC. Is there a specific rate limit or capacity constraint on the Architect engine in the AP-SG region that I am hitting? I have tried increasing the timeout in JMeter to 60 seconds, but the issue persists. Any insights on how to tune the flow or check for backend bottlenecks would be appreciated. I am new to this scale of testing so I might be missing a basic configuration step.