Photos duplicated after 14.0.1 update

True, but I doubt that could be the case here. The OP says that all of a sudden the virtual copies are there, and that they contain the edits and the originals have no edits. If soft proofing was enabled at some point and then an extra edit was made which created the soft proof virtual copies, then the originals would still contain all the edits, and the virtual copies would contain the same edits plus that one extra edit. In that case simply deleting all the virtual copies would solve it, but the OP already said that this is no option because he would lose all the edits if he did that. 

All four of those copy's in that screenshot are virtual, notice the bottom right corner of the thumbnail.

So, you do not remember making those virtual copy's? A difference between LrC creating an outright copy and creating or the user creating a virtual copy.

One suspicion, an accidental batch creation of virtual copy's.

Now, I am not at a computer to test, but to work thru what victuals are unwanted, perhaps filter on virtual, label those, then filter thru the labeled for no edits.

AD, I'm confused so I went back to your original post.
" images appear as duplicates 1of2 and 2of2."

The "2" is the "developed" (virtual) image." <-- Original (Master) and virtual copies can be developed. Developed and Virtual are not synonyms.

Prior to using Photo>Create Virtual Copy, Copy 1 and Copy 2 do not exist. Creating a virtual copy creates a new catalog entry but does not create a new file.

The original file and the virtual copy share the exact same name; same extension.

In Loupe view, the original file displays as filename.ext and the virtual copy as filename.ext • Copy 1.

The original file will never appear in the Loupe view as filename.ext • Copy anything.

In Grid view, the upper-left corner displays the number of catalog entries (original and duplicates).

In Grid view, hovering the cursor over the original changes the number of catalog entries to display the total number of copies, i.e., "1 of 2" and the filename.ext.

The virtual copy will display "2 of 2" and filename.ext • Copy 1

Of course all virtual copies point to the original file in the folder.As MacLeod said, There Can Be Only One.

Deleting copies retains the original file but yes, their copy edits are lost.

As far as deleting entries, deleting a copy will get a warning from LrC:

Remove the selected copy? with the choices, Remove from Lightroom and Cancel

Deleting the original will get this warning:

Remove Photo from Lightroom Catalog
This photo will be removed from your Lightroom Catalog and any synced Lightroom Clients. Select "Delete from Disk" to also move the selected photos on your computer to the Finder's trash.
One virtual copy will also be removed.

with the choices, Remove from Lightroom, Delete from Disk and Cancel.

The copies take up next-to-nothing storage space, only increase the catalog size negligibly.

Create virtual copies

https://helpx.adobe.com/lightroom-classic/help/photos.html?x-product=Helpx%2F1.0.0&x-product-location=Search%3AForums%3Alink%2F3.5.6 

"...You can even make one of the virtual copies a master, making the previous master a virtual copy.
Virtual copies become actual photos when they are exported as a copy of the master photo or edited as a copy in an external editor.

In the Library module, select a virtual copy of a photo in the Grid view or the Filmstrip and choose Photo > Set Copy As Master."