The framing needs one correction that changes everything, because a shortcut cannot be converted into a file, it never contained one and understanding that points at the real recovery:

What a shortcut actually is: a shortcut is a tiny pointer file that references another file's location, containing no data of the original itself, so there is nothing inside a shortcut to convert back into the file. If the shortcuts appeared where your real files were, the real files were not turned into shortcuts, they were hidden and shortcuts were placed alongside, which is the shortcut virus pattern, meaning your real files are elsewhere on the drive, hidden, waiting to be revealed rather than converted.

The real recovery, revealing the hidden originals: since the files still exist hidden, the recovery is the attrib command that unhides them, attrib -h -s -r /s /d *.* from an admin command prompt on the affected drive, which clears the hidden and system attributes and makes your real files reappear alongside the shortcuts, covered fully in the shortcut virus thread linked alongside. Then you delete the useless shortcuts and keep your revealed files, which is the actual conversion you wanted, not shortcut into file but hidden file back into view.

The case where a shortcut points at a real surviving file: if a shortcut genuinely points at a file that still exists somewhere, right clicking the shortcut, Properties, shows the Target, the path to the real file, which you then navigate to and use directly, the shortcut having served only as a pointer. This is the benign case where a shortcut is just a shortcut, distinct from the virus case where the shortcuts are malware decoys and the reveal is the recovery.

The malware cleanup that must follow the virus case: if this was the shortcut virus, revealing the files is half the job, running a malware scan to remove what hid them is the other half, since the files reappear but the malware remains ready to rehide them and spread to other drives, the incomplete fix that makes the problem seem to return.