shortcut.link

I initially suspected these files were a Windows .lnk file what in Mac speak known as 'aliases' and not the real files. These will have likely come from a Windows machine - consistent with your mentioning they came from a Dell.

See - https://fileinfo.com/extension/lnk

They are in effect very small text files and merely contain information saying 'this is where the real file is'. There is no way to convert them back to the real files. You will need to re-copy i.e. 'properly' copy the real files from the Dell.

What a brody is referring to is a similar shortcut which points to a webpage, Mac web browsers actually use the file extension .webloc for these types of file. Again it will be a very small file and cannot be restored to the file file but merely points to a webpage or similar Internet resource.

I did however find this - https://fileinfo.com/extension/link

This mentions them to be again a small file that points to the real thing but this time specific to iTunes music. I have never seen one of these myself despite using iTunes for years and years. Again it will not be possible to convert it back to the real file, you will need to go back to the Dell and recopy the file and make sure the this time they are properly copied.

At a guess you may have dragged the tracks from inside the iTunes window on to the Transcend drive or perhaps you were playing them from the iTunes Music or iTunes Store and they were not downloaded to your Dell.

Shortcut.link files are not the actual song files themselves. They are bookmark links to the websites that hosted those files. If you open those files with a web browser you might be able to retrieve the songs if they were still there.

You needed to download as source while still at the Dell. You might be able to use a tool such as Textwrangler or BBEdit to open these files to extract the http:// address from the original link of those files.