SageMaker CreateModelPackage input argument semantics and SageMaker SDK AlgorithmEstimator

In SageMaker, creating a model package from an algorithm looks like this:

boto3.Session().client('sagemaker').create_model_package(
    ModelPackageName = ''name",
    ModelPackageDescription = ''desc",
    SourceAlgorithmSpecification = {
        'SourceAlgorithms': [{
            'AlgorithmName': 'AlgorithmName',
            'ModelDataUrl': 's3://path/to/model/data'
        }]
    }
)

My problem is around what to provide as AlgorithmName. Looking at the API docs here shows the argument regex accepts both an ARN and a Name. The problem is when to use what

If I were to use an algorithm from the marketplace then passing over the algorithm ARN succeeds, but passing over the algorithm name fails with:

ClientError: An error occurred (ValidationException) when calling the CreateModelPackage operation: Algorithm arn:aws:sagemaker:eu-central-1:123456789012:algorithm/scikit-decision-trees-15423055-57b73412d2e93e9239e4e16f83298b8f does not exist.

However, if I have a custom algorithm I created myself (meaning not from the marketplace), then it is the other way around - using its name fails while using the ARN succeeds.

Had it been just this mixup I would have solved it by using the right one in the right context. However, when using the SageMaker SDK I have no control over what is passed to the API call. Specifically, when I try to use a custom algorithm with the AlgorithmEstimator().fit().transform() paradigm a create_model_package call is made with the custom algorithm ARN - which fails. This prevents me from using SageMaker SDK with custom algorithms. I don't know whether the solution is to have the API accept both options in both scenarios or for the SageMaker SDK to use the algorithm's name instead of the ARN.