Hi,
The rate limits for our APIs are not configurable in tenant settings. You can find the Authentication rate limits here: Rate Limit Policy
What you can do to minimize the number of Client Credential requests made for M2M Tokens is to cache the tokens that you receive until they expire and then request for new ones. There is no built-in way to achieve caching M2M tokens like this in Auth0 at the moment.
You can also take a look at a related question and answer here.