Is your feature request related to a problem? Please describe.
At the present, CDK only supports L1 Constructs ElastiCache Serverless.

Would you be willing to help with a PR?

• Yes, absolutely
• Yes, with some guidance
• Unfortunately no time :'-(

Describe the solution you'd like

Add L2 Constructs related to the following L1 Constructs.

• CfnServerlessCache
• CfnUserGroup
• CfnUser

Describe alternatives you've considered

Use L1 Constructs.

Additional context

While an RFC exists for ElastiCache L2 Constructs, this only covers Provisioned instances and not Serverless.

The L2 Constructs planned for implementation in this issue are not included in the RFC.

aws/aws-cdk-rfcs#456
https://github.com/aws/aws-cdk-rfcs/blob/main/text/0456-elasticache-l2.md