Transfer WhatsApp Business chat history to new iPhone without iCloud?

Hello,

My wife's company was bought several times within about 3 years and she is still employed by the new company.

She continued to use the iPhone SE (1st generation) from her first company, which was still registered to her old employer's organization. However, IT no longer supports it, or rather, the password has expired, and she also has a new email address/account, etc.

Now she wants to have the WhatsApp Business chat history on her new iPhone so that she can give up the old one or retire it.

Unfortunately, you cannot do an iCloud backup because IT no longer manages it.

How can you get the chats including pictures onto the new phone?

Exporting works, but then you get a zip file with everything in it, which I can't do anything with, or I can't find the import function in WA B. Is there any way to import zip files to a new WA B. device?

Greetings