EMR Serverless on Spot capacity?

Thank you raising this question on re:Post.

AWS Serverless is a managed service and hence the resources are managed by the EMR Service. From the documentation I can only see choices limited to the architecture (x86 or arm64) and there are no choices on instance-types in use. This is a design choice to abstract out the complexity to manage a cluster from AWS users, so that the users can focus more on their business solutions and not on managing the clusters.

I understand the question about spot instance may be related to pricing and if you can expect cheaper option in the future. Unfortunately, the information on upcoming changes and features are internal to AWS EMR Service Team. I would recommend you to monitor the release page for EMR Serverless