OAuth Token Refresh 401 during load test

Is there a clean way to handle token expiry in JMeter scripts for Genesys Cloud?

Running a load test in Singapore with 100 concurrent users. After 5 minutes, the /api/v2/users/me endpoint starts failing. The initial login works, but refresh tokens seem to get invalidated or rejected under high concurrency.

401 Unauthorized: {"code":"unauthorized","message":"Access token expired"}

Should I cache tokens or refresh per thread?