Ultimately, all the datasets on Steam are scraped one way or another, since Steam themselves don't seem to publish it. I could be that they simply never came across your project before you delisted it, and of course after delisiting it I don't think they'll ever come across it.

Hm yeah. We removed it a few years ago now so I assume they should have found it though. We followed these instructions and had to contact valve and give a justification https://partner.steamgames.com/doc/store/retire_app I don’t remember the details of the form but maybe there were options and one amounts to being delisted and another amounts to just no longer being visible and available for sale.