One thing to have in mind that may even be more important than the current 429 you’re receiving is that performance/load testing against an Auth0 tenant is only available to certain subscriptions and even for those it needs to be pre-approved (Load Testing Policy).
If you are eligible to perform them the best course of action for technical queries related to execution of such test would be to make them in the same support ticket requesting the test approval.
If you are not eligible to perform a load test than receiving 429 response is not the worse that it can happen, because technically you’re performing something you should not and as such may have the tenant itself blocked.