Does Apple Pay (I think this is Wallet) require data?

No, you can easily use Apple Pay offline.

Apple Pay uses the built-in NFC chip, where card data is stored - just like on a real credit card. So it is not necessary to have a connection to 5G/4G or WiFi when it needs to be used.

You're welcome.

No, it is not necessary. Setting up Apple Pay for the first time does require a data connection, but it is self-explanatory.