I was previously part of an organization with 500+ devs with more than 25+ AWS accounts for each client which had to be managed by the DevOps team. The number of people in DevOps team was smaller than the accounts and all of them were mostly active with resources being allocated and deallocated frequently. We utilised many AWS services like EC2, S3, EKS, SageMaker, RDS, Redshift, Cloudfront, Route53, SSM etc