how to retrieve timezone when object timezone is emtpy

Hello,  we are using localize data to display date time in our app.  But the excel export is using the date time of the server by default. (no way to change it) To fix that problem I was thinking of adding / removing the difference of time by using the timezone object (linked to the user) but unfortunately, it is often empty. Any suggestion?  thanks
1 answers

You should read this section of the documentation:

If you do not have a default time zone and it was not specified for the user, the reference will be empty. 


But main question here is, what is the use case? 

If you would be able to change it the export behavior, it would probably only allow you to export the data using the time zone of your current user.

You could try generating a word/pdf document in a table format?