Hi,
The data source arn is a quicksight data source arn, not the ARN of the RDS DB. Should be something like this.
arn:aws:quicksight:us-west-2:###########:datasource/3f979181-####-####-####-90be58497350
So you should also be creating the DataSource in the CF, and use that ARN as the data source for your data set if you dont have it created already on the prod account, if so, you can use the arn of that datasource for your CFN template.
Hope this helps!
Hope this helps!