cloudformation-yaml-wafv2 parametrized DefaultAction using custom action

wafv2.yaml

Description: Create WebACL example
Parameters:
  WebACLDefaultAction:
    Type: String
    AllowedValues:
      - Allow
      - Block
  
  WebACLRuleAction:
    Type: String
    AllowedValues:
      - Allow
      - Count
      - Block

Conditions:
  DefaultActionisAllow: !Equals [!Ref WebACLDefaultAction, 'Allow']
  RuleActionisAllow: !Equals [!Ref WebACLRuleAction, 'Allow']
  RuleActionisBlock: !Equals [!Ref WebACLRuleAction, 'Block']

Resources:
  ExampleWebACL:
    Type: AWS::WAFv2::WebACL
    Properties:
      Name: ExampleWebACL
      Scope: REGIONAL
      Description: This is an example WebACL
      DefaultAction:
        !If
          - DefaultActionisAllow
          - Allow: {}
          - Block: {}
      VisibilityConfig:
        SampledRequestsEnabled: true
        CloudWatchMetricsEnabled: true
        MetricName: ExampleWebACLMetric
      Rules:
        - Name: BlockXssAttack
          Priority: 1
          Action:
            !If
              - RuleActionisAllow
              - Allow: {}
              - !If
                  - RuleActionisBlock
                  - Block: {}
                  - Count: {}
          VisibilityConfig:
            SampledRequestsEnabled: true
            CloudWatchMetricsEnabled: true
            MetricName: BlockXssAttackMetric
          Statement:
            XssMatchStatement:
              FieldToMatch:
                AllQueryArguments: {}
              TextTransformations:
                - Priority: 1
                  Type: NONE



        - Name: AWS-AWSManagedRulesAnonymousIpList
          Priority: 300
          OverrideAction:
            !If
              - RuleActionisAllow
              - Count: {}
              - None: {}
          VisibilityConfig:
            SampledRequestsEnabled: true
            CloudWatchMetricsEnabled: true
            MetricName: AWSManagedRulesAnonymousIpListMetric
          Statement:
            ManagedRuleGroupStatement:
              VendorName: AWS
              Name: AWSManagedRulesAnonymousIpList
              ExcludedRules: []