A quick count on mine (import 128GB) is about 70 languages, for Interface Language. Then, when selecting one, there are regional variations available. Example: Deutsch > Deutschland, Liechtenstein, Osterreich, Belgien, Luxemburg. The language selection applies to all interfaces and menus. The phone comes initially configured to Chinese or something, but is easy to change to your preferred language before the setup process.
I ordered the 128GB import version. Digitec opened the package and included a correct CH power adapter (2-pin with Quickcharge). The original Samsung seal was already damaged and Digitec added its own guarantee seal with a corresponding note.
I can't answer your second question because I don't use Samsung Pay.
Because many mobile phones were not always intended for the Swiss market and Samsung Pay is not yet available in all countries. If you have a mobile phone from Germany, for example, it is not yet compatible with Samsung Pay. But this will all change as soon as Samsung Pay is available everywhere.