Open up the Photo folder in file explorer. Along the top, right-click one of the file data fields (name, type, size, etc). In the pop-up menu will be an option for "More...". Click that.
You'll get a new dialog box allowing you to add all sorts of new data fields for that folder. Enable one which might be able to help you distinguish new files from freshly copied ones. I'm not sure exactly how all of them work, but maybe date archived, or date created, or date last saved. You're gonna have to play around with different ones until you find one whose timestamp corresponds to when you accidentally copied the files over.
Assuming you find one and add it, then all you then have to do is click on that field in file explorer to sort...