The device is a Galaxy S25 Ultra from Canada. Its hardware and software are specific to the Canadian Market and the device shouldn't be sold in the rest of the world. Country-specific models tend to have only a selected set of languages which can be used. On the other hand International models, or models which are shared between countries which speak different languages, tend to have the compatibility with all the languages. Unfortunately there is nothing you can do. As the phone says only some apps might use Italian. The best thing to do, if you need the Italian language, is to return the product and buy it again as a new device from a trustworthy shop like Samsung Shop Italy or on Amazon.it making sure the seller is Amazon Italia.