When Illustrator is relaunched after a crash, it will look for recovery files. If it finds some, it will ask you what to do. You must then click on "Try to recover" or the files will be gone for good,. Then Illustrator will try to recover the files. If it cannot, then that is that.
Renaming that file won't help you.
Remember to make backups. Always. And make more backups. And save regularly. Recover can fail, it's not meant as a replacement for a proper backup strategy. It's not autosave.
I am sorry for the delayed response, as I was not getting any emails or notifications since 22 July. If you still have those files, would you mind uploading them on Creative Cloud and sharing the download link here or via DM? We will try our best to recover the files. I must also inform you that file recovery can't be guaranteed with 100% success. We'll surely try our best.