How to handle legacy language variant in Studio 2021 & Windows 10

Hi 

I'm re-posting this question also in this group in hope, that someone of you could come up with a suggestion or useful thought. 

SITUATION:

  • Due to customer compatibility requirements,  we still need to create a Studio projects that use Serbian (Latin, Serbia and Montenegro (Former)) as target language.
  • What we believe is the root cause for the issue here is that we have upgraded our working environment to Windows 10, where for some reason, you don't get Serbian (Latin, Serbia and Montenegro (Former)) as a target language option. 
  • It is a requirement, that we must continue to use Serbian (Latin, Serbia and Montenegro (Former)) as target language also in newly created projects.

WHAT IS HAPPENING?

-  The same version of Studio, when running in  Windows 7, does show Serbian (Latin, Serbia and Montenegro (Former)) language out of the box.

- When trying the same version of Studio in Windows 10, the Serbian (Latin, Serbia and Montenegro (Former)) language is not shown when creating new project, but when I open a project created on Windows 7 and using Serbian (Former) as target language, Studio shows it and can handle it.


- there must be a way to get the Serbian (Latin, Serbia and Montenegro (Former)) language also when Studio is installed on Windows 10, as I can see this language when I open a project created on Windows 7 with (Former as desired target language).    

 QUESTIONS:

Can somebody suggest any option, that would allow us to create new Studio project on Windows 10, where we would be able to select the "hiden" Serbian (Latin, Serbia and Montenegro (Former)) as target language?

Could this be done, by tweaking .NET settings on the machine?

Or would it be a better option if we would look into some sort of "Studio Plugin" which would then "expose" this  hidden (Former) language for new project creation in Studio? 

Thank you for any thoughts and suggestion you might decide to give me.

Simon

P.s. 
I know we could have one virtual machine with Windows 7 and Studio and our automation running, but does not solve our problem - we need to run the automation  on different machines, depending who is going to to handle the job.

P.p.s

In case anybody is wandering about the language id for this language, here is my cheat sheet. 

Serbian (Latin, Serbia and Montenegro (Former))

xml:lang="sr-Latn-CS">

Win 7 

Serbian (Cyrilic, Serbia)

xml:lang="sr-Cyrl-RS">

Win 10

Serbian (Latin, Serbia)

xml:lang="sr-Latn-RS">

Win 10

Serbian (Latin, Bosnia and Herzegovina)

xml:lang="sr-Latn-BA">

Win 10

Serbian (Latin, Kosovo)

xml:lang="sr-Latn-XK">

Win 10

Serbian (Latin, Montenegro)

xml:lang="sr-Latn-ME">

Win 10