Potential risks with owning an Expired Domain marketplace.

Hello, what are the potential risks, or points which should be examined when opening an expired domains marketplace?
I see there are several BST's on bhw advertising websites which sell expired domains, but most of them are closed after several pages.
Is that due to the platform reuqiring anonymity or what? thanks.

The main risks include purchasing domains with SEO penalties (Google penalties), domains with trademark infringement, security risks from a bad history, and high maintenance costs with poor liquidity.