Hello @Flavio Bonacordi ,
Thank you for posting here.
Based on the description, you can try the following way.
If your system in the offline environment where cannot connect to the internet, please download and install the language pack ISO by using method 2 in the Microsoft Technical Information.
Cannot configure a language pack for Windows Server 2019 Desktop Experience
https://learn.microsoft.com/en-US/troubleshoot/windows-server/shell-experience/cannot-configure-language-pack-windows-server-desktop-experience
After the installation, return to step 5 and select your language, and click Next. If the following message is displayed, ignore it and click Install.
You’re currently offline. When you’re connected, go to Language settings, select the language in the list, select Options, and finish downloading.
After that, check if the supplemental fonts you want is also installed.
Or I assume server1 is with Internet, server2 is not with Internet.
You can try to use the image with the corresponding languages and supplemental fonts installed on server1 to install on server2.
Hope the information above is helpful.
Should you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou