I've followed the steps on https://help.salesforce.com/s/articleView?id=000381035&type=1 to be able to create and populate a data extension with Subscribers from the Hidden Triggered Send Managed List.
However, I'm unsure on how to proceed with the instructions provided for deleting the Contact via Contact Builder. The crucial point here is that the back-end Marketing Cloud SubscriberId is different in the Hidden Triggered Send Managed List for the Subscriber I wish to delete vs the main Subscriber record. I therefore only have this Id as a way of isolating the specific record I need to delete (as the SubscriberKey is the same for both records), but there's no way to search via SubscriberId in Contact Builder.
Without affecting the main Subscriber record in All Subscribers, how can I isolate and delete just the record in the Hidden Triggered Send Managed List?