Retention and disposal at scale, AI may be

We have hundreds of thousands of archive/old documents held in SharePoint that have reached end of their retention period and could be disposed-off. I am wondering if anyone has tackled such a challenge before. Reviewing such a large volume of content in Purview is impractical and we are wondering if AI could be of some help here. May be a solution whereby AI can extract and present metadata from these documents for our business to analyse in bulk. Any ideas?