Bunq card

Based on your country of residence or country you have selected under your Apple ID --> Payment methods that you can use with your Apple ID - Apple ...

Ask your bank only one thing, i.e. if the Debit/Credit card which is issued to you is valid internationally.

Rest everything check at your end.

Check the following

1. The payment method that you are adding is of the same country as that of App Store Country on your iPhone
2. You have valid payment plan / debit / credit card from an authorised bank from the same country as that of your Apple ID
3. Learn more about family purchases and payments.

Contact iTunes Store Support Team using this link:--> iTunes Store & App Store – Get support for various issues

(select: your country, then Apple ID, then iTunes & App Store. If your problem is not among the options shown there, tap/click on the option “the topic is not listed” and describe your issue).

Regards

Giulio