Hello TJensen
I know it has been a while and there has been no response to this post. I am not sure if you've found a solution/workaround or you contacted Support for this.
Have you tried Classification, Retention & Expiry? That would be the easiest way to get this moving.
Another option would be try a 3rd Party Tool, Globanet's Classify, which will allow to classify these kind of items based on certain rules and and then delete those items. You can refer to this link for more information about Classify; https://globanet.com/classify/