EN content is shown with NL setting, not in the EN setting

Requirements: 
As a site admin,  when editor or author copies a page or a document and place it in another folder, I want the locale of the document or page to be updated to the locale of the folder that copy is located so that the locales of the documents and pages will not conflict with the folder locale. 

Saas already has the functionality. See the video for expected behavior: https://drive.google.com/file/d/1IbNrG-3jJ621T8g8q35sZFR98GEvgnFz/view?usp=sharing
Edge case: 
If the no locale is available , the keep the doc as it is.

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Scenario:
0. In the CMS there are multiple language folders ( e.g. NL, EN).
1. Create a document in the NL language
2. Copy document using the Copy option from the document -> when selecting the location for the new document select a folder indie the EN translated folder structure
3. The copied document still had the NL language but the customer expected the document language to be dictated based on the language of the folder

Proposed options /questions by our development team :
1. In the scenario presented above to have a validation activated to send an error to the client that the desired document cannot be moved to the EN folder because the language is in NL => Deny the user to copy the document to that folder
2. In the pop-up window to select the new location of the copied document to have displayed only the options for that folders in the same language
3. To automatically convert the copied document in the language of the folder in which we want to move it

Final requirement:

Show a warning message in copy/move document modals to inform use that the locale of the document will not be changed by copying or moving it.