My usecase for AWS Batch

You could use AWS Batch as an alternative to EC2. Batch would take care of load balancing the EC2 fleet, queuing tasks and packing tasks onto instances based on the memory and CPU requirements of the task. If your tasks are fault tolerant you could also use a Spot Compute Environment and take advantage of spot pricing.

An alternative could be using AWS Lambda if your tasks are small and will complete within the maximum allowed lifespan of Lambda functions.