Parameterize list of replica regions in DynamoDB SAM Template

I am trying to parameterize value of regions in Replica/Region property of DynamoDB SAM Template using 2 methods - one using sam toml file, another with hardcoded values.

1. Using samconfig.toml as:

• parameter-overrides section to have "ddbregionlist="us-east-1,us-east-2""
• template.yml to have

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: SAM Template for deployment of DynamoDB resources

Parameters:
  ddbregionlist:
    Type: CommaDelimitedList
    Default: "us-east-1, us-east-2"

Resources:
  #-------------------** DynamoDB Table **--------------------

  DDBTable:
    Type: AWS::DynamoDB::GlobalTable
    Properties:
      TableName: ddbtable
      AttributeDefinitions:
        - AttributeName: "id"
          AttributeType: "S"
      KeySchema:
        - AttributeName: "id"
          KeyType: "HASH"
      BillingMode: "PAY_PER_REQUEST"
      StreamSpecification: 
        StreamViewType: NEW_AND_OLD_IMAGES
      Replicas:
        - Region: !Select [ 0, !Ref ddbregionlist ]
        - Region: !Select [ 1, !Ref ddbregionlist ]

2. With direct hardcoded values for Replica Regions - everything same template as above with difference as below -

Replicas:
        - Region: !Select [ 0, [ "us-east-1", "us-east-2" ] ]
        - Region: !Select [ 1, [ "us-east-1", "us-east-2" ] ]

None of the above methods is working and here the portion of log which I am seeing.

Unable to resolve property Region: OrderedDict([('Fn::Select', ['0', ['us-east-1', 'us-east-2']])]). Leaving as is.

Resource handler returned message: "Resource of type 'AWS::DynamoDB::GlobalTable' with identifier 'ddbtable' did not stabilize." (RequestToken: <....>, HandlerErrorCode: NotStabilized)

Possibly, samconfig values are not getting passed, however, hardcoded values in #2 should have worked as per this link - [https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-select.html].

I suppose, I am using correct syntax. Can someone please help me resolve this ? Thanks in advance.