PDF repair? Nothing working

Hi, hoping someone can suggest something please.

I was transferring PDFs from one laptop to another using a new USB pen.

Something went disastrously wrong. I don’t know what the pen did, but the files are unopenable.

I’ve tried as much as I can, and nothing will read or repair them.

It’s bizarre, because the PDFs look normal in the folder, with all their proper file sizes, but they just will not open.

It’s a loss. There are about 350 files, and I don’t have access to the source any more to replace.

The files do unfortunately seem to be garbage, but any advice would be appreciated.

Thanks,
Dene.