[Feature Request] Is there any stats available for Amazon Bedrock Knowledge Database cost?

## Describe the solution you'd like

I set up the full project stack keeping all settings default. Among them, enableRagReplicas=true. As a consequence, all my OpenSearch collections are set up with "Deployment type = Enabled redundancy" Currently, I have two collections in place, one is 2.9mb in size (1 document), the other one 2.3mb (3 documents).
I am interested in a more cost-effective vectorstore solution, as I want to scale to thousands of documents.

## Why the solution needed

With my current setup, I have Opensearch cost of already **11.50 US$ in Region Frankfurt**. Either I have done something wrong or otherwise I would consider this cost level as not acceptable.

## Additional context

To be able to compare, I created a new Opensearch collection today, with enableRagReplicas=false. I would assume that this collection will have half of the cost than the redundant option, but I will see in a couple of days, or otherwise any comment on this cost level is appreciated. The Opensearch cost related documentation I found so far is not really going into that detail.

## Implementation feasibility

Are you willing to collaborate with us to discuss the solution, decide on the approach, and assist with the implementation?

- [ ] Yes, I am able to implement the feature and create a pull request.
- [X] No, I am unable to implement the feature, but I am open to discussing the solution.