Hello! Thanks for reaching out with these questions!
1.) If you need an Atlas Admin API rate limit increase, you can request that via the MongoDB Support Portal. Our support team will be happy to address your concerns, and help unblock your workflow if possible.
2.) The Atlas Admin API does not natively support batch requests, so those calls each need to be sent individually resulting in a 1:1 request-response. Any bulk actions would need to be implemented on the client side via a custom workflow.
I hope this helps, and if you have any additional questions please don’t hesitate to reach out!