How to get endpoint for aws elasticache serverless cache?

How can I get endpoint for an aws_elasticache_serverless_cache resource? I want to pass this endpoint as an env var to one of my k8s deployments like so

                  { name: "REDIS_URL", value: config.cache.endpoint.get(0).computeFqn()},

where my config is of type

export type RpcProxy2Config = {
  // ...other stuff
  cache: ElasticacheServerlessCache;
};

The above example gets the following error:

[2024-06-05T09:49:29.747] [ERROR] default - ╷
│ Error: Incorrect attribute value type
│
│   on cdk.tf.json line 5699, in resource.kubernetes_deployment.rpc-proxy-2_D64F493D.spec.template.spec.container[0].env[2]:
│ 5699:                       "value": "${aws_elasticache_serverless_cache.rpc-proxy-2-cache.endpoint[0]}"
│     ├────────────────
│     │ aws_elasticache_serverless_cache.rpc-proxy-2-cache.endpoint[0] is a object
│
│ Inappropriate value for attribute "value": string required.
goldsky-infra-dev  ╷
                   │ Error: Incorrect attribute value type
                   │
                   │   on cdk.tf.json line 5699, in resource.kubernetes_deployment.rpc-proxy-2_D64F493D (rpc-proxy-2/rpc-proxy-2).spec.template.spec.container[0].env[2]:
                   │ 5699:                       "value": "${aws_elasticache_serverless_cache.rpc-proxy-2-cache (rpc-proxy-2-cache).endpoint[0]}"
                   │     ├────────────────
                   │     │ aws_elasticache_serverless_cache.rpc-proxy-2-cache.endpoint[0] is a object
                   │
                   │ Inappropriate value for attribute "value": string required.
                   ╵

⠦  Processing

I’ve tried using config.cache.endpoint.get(0).fqn as well and config.cache.endpoint.get(0).address but they have the same issue. It seems that I can’t get properties on the object returned after the .get call.

Here are my dependencies

  "dependencies": {
    "@cdktf/provider-aws": "^19.21.0",
    "@cdktf/provider-kubernetes": "^11.5.0",
    "@eryldor/cidr": "^1.0.5",
    "cdktf": "^0.20.7",
    "cdktf-cli": "^0.20.7",
    "constructs": "^10.0.9",
    "ejs": "^3.1.6",
    "pg": "^8.10.0"
  },