@OdiS9903 the suggestion which was provided to you in the support ticket INC-201537 was that there is no OOTB tools to meet this requirement which is why you were asked to put your question here on the forum, for other clients to comment on.
It was suggested that you can create an activity to utilizes obj-browse and obj-delete for all those Data Class instances which you want to purge.
If you wish you can log this as a new Idea here so that the product owners can review whether this would be a feasible enhancement for future products.
Be aware though that there might be push-back from our engineering team, with the reasons given in the following post
@RahmatS8 and @OdiS9903 , In 8.7.1, the new case archival functionality supports including custom classes associated with a case type in the archival process. See attached schematics for support in 8.7 and 8.7.1.