How to set LambdaConfig of a userpool in the AWS Cognito Console

My Cloudformation template.yml correctly instantiates a Cognito userpool like the next one:

 UserPool:
    Type: "AWS::Cognito::UserPool"
    Properties:
      UserPoolName: auth-template-user-pool
      UsernameAttributes:
        - email
      AutoVerifiedAttributes:
        - email
      VerificationMessageTemplate:
        DefaultEmailOption: CONFIRM_WITH_CODE
      EmailConfiguration:
        EmailSendingAccount: COGNITO_DEFAULT
      LambdaConfig:
        KMSKeyID: !GetAtt KMSKey.Arn
        CustomEmailSender:
          LambdaArn: !GetAtt CustomEmailSender.Arn
          LambdaVersion: "V1_0"

In particular, I want to focus on the LambdaConfig property that explicits the use of a certain KMSKey to encode/decode the CONFIRM CODEs sent in the CustomEmailSender AWS Lambda.

What I want to achieve, is to obtain the exact same results, that is: to set the equivalent correct values for the LambdaConfig you see above, but using the AWS Cognito console (no cli). Documentation is no help in doing this, and I am not able to find anything useful in the cloud console.

That is not possible. Not everything you can do via APIs and via the CLI can be done via the UI / Console as well.

The trigger shows up within the "User pool properties" tab when you created one via CF or the CLI. But it is not manageable via the UI, the corresponding radio button to select it is simply greyed out.

Another example which I recently complained about to AWS Support is SES Email Templates: can only be created, inspected and deleted via the CLI, the UI only displays their name and nothing else. If you feel like this feature is important and missing you need to contact AWS and tell them, that way the corresponding feature request gets a +1 and maybe maybe maybe will be implemented at some point.