How to automatically add aws(can be any cloud) provider details into terragrunt.hcl

I have Terragrunt folder structure like below,

|-- eu-west-1
|   |-- product
|   |   |-- prod
|   |   |   |-- 5.7
|   |   |   |-- 6.2
|   |   |   |-- development
|   |   |   |   |-- fargate-clusters
|   |   |   |   |   |-- module.tf.json
|   |   |   |   |   `-- terragrunt.hcl
|   |   |   |   `-- uiapp
|   |   |   |       |-- terragrunt.hcl
|   |   |   |       `-- module.tf.json
|   |   |   `-- env.hcl
|   |   |-- dev
|   |   |   |-- 5.7
|   |   |   |   |-- fargate-clusters
|   |   |   |   |   |-- module.tf.json
|   |   |   |   |   `-- terragrunt.hcl
|   |   |   |   `-- uiapp
|   |   |   |       |-- terragrunt.hcl
|   |   |   |       `-- module.tf.json
|   |   |   |-- development
|   |   |   |   |-- fargate-clusters
|   |   |   |   |   |-- module.tf.json
|   |   |   |   |   `-- terragrunt.hcl
|   |   |   |   `-- uiapp
|   |   |   |       |-- terragrunt.hcl
|   |   |   |       `-- module.tf.json
|   |   |   `-- env.hcl
|   |-- region.hcl
|-- README.md
`-- terragrunt.hcl

And I have multiple accounts configured inside my terragrunt.hcl

provider "aws" {
  alias  = "product-dev"
  region = "${local.aws_region}"
  assume_role {
    role_arn     = "arn:aws:iam::123456789:role/TerraformRole"
  }
}

There are more than AWS 50 accounts we are managing and we keep on adding new accounts into Terragrunt.

Is there a known pattern already to dynamically tell terraform/terragrunt about the new acccount id and the IAM role to assume?

As of now, every time I have to manually add the provider into terragrunt.hcl and account id into env.hcl