Firehose destinations (alpha) enable dynamic partitioning

[nicklasweasel]

I have

LambdaFunctionProcessor processor = LambdaFunctionProcessor.Builder.create(tranformationLambda).bufferInterval(Duration.minutes(1)).bufferSize(Size.mebibytes(1)).build();
        S3Bucket ticketActivityDestinationBucket = S3Bucket.Builder.create(ticketActivityBucket)
                .dataOutputPrefix("year=!{partitionKeyFromLambda:year}/month=!{partitionKeyFromLambda:month}/day=!{partitionKeyFromLambda:day}/portId=!{partitionKeyFromLambda:portId}/operatorId=!{partitionKeyFromLambda:operatorId}/")
                .errorOutputPrefix("/errors")
                .processor(processor)
                .bufferingInterval(Duration.minutes(5))
                .bufferingSize(Size.mebibytes(1))
                .build();

        DeliveryStream.Builder.create(scope, "TicketActivityDeliveryStream")
                .deliveryStreamName("TicketActivity")
                .sourceStream(ticketActivityStream)
                .destinations(List.of(ticketActivityDestinationBucket))
                .build();

where the processor sets the .metadata.partitionKeys for future reference

but it results in

Dynamic Partitioning Namespaces can only be part of a prefix expression when Dynamic Partitioning is enabled

However, I find no way in either builders to enable the dynamic partitioning. Is escape hatching the only way?