Hello. I explored a site with STL models and found, what it will be about a few hundred models.
Crawling in each section and collecting data about needed download is not so easy, as it seems on the first view. But Ok, all doable in the right amount of time.
Minifactory is offering free models to download, but sketchfab - is often is asking for payment (or model is not available to download in STL format).
But the next step - converting open STL format to proprietary Autodesk FBX. The most challenging part, I think. An online converter is good, but does not provide API - so we have to upload and download each file manually. Local Blender install is probably, better options, as it can be scripted (I think)
Renaming, organizing to folders, zipping, and uploading is the easiest part, but also consuming time.
So I'm offering my service to you but with different terms. Or total for a fixed price with the indicated amount, or variable - per finished model ($0.5 per each). Of course, if you need quality work
Thank you