Management API rate limits are outlined in this doc: Rate Limit Policy and depend on what type of subscription plan you have.
This doc also outlines additional limits for certain tenant types: Rate Limit Policy
Using the Management API for free and trial tenants is restricted to 2 requests per second (with bursts of up to 10 requests ). Exceeding these values triggers an HTTP 429 error, but the error message states, “Global limit has been reached.” These are in addition to those indicated in the rate limit response headers.
That doc includes information about how to use the response headers to handle the limits.