Unable to add funds to Apple Account using iDeal in an Apple Family

You can't use iDeal as a payment method, only for adding funds to your account.

Payment methods that you can use with your Apple Account - Apple Support

Add money to your Apple Account balance - Apple Support

If you are not the Family Sharing organizer, you cannot add a payment method to your account anyway. Only one person, the Organizer, can (and must) have a card, but the Organizer can avoid having this charged by others by asking them to make sure they have adequate personal balance (e.g., from gift cards) to cover their purchases. Other family members can only pay for things by using their personal balance or by letting the remainder automatically roll over to the Organizer's payment method (such as a credit card but not the Organizer's personal account balance).

Based on: How to share apps and purchases with Family Sharing - Apple Support and How apps, content, and subscriptions from Apple are billed - Apple Support

I don't know if because you are in Family Sharing group if that is what is preventing you from adding a payment method, even if it isn't a standard primary method such as would be used directly. Ask Apple about this. Your iDeal card is not something with which I am familiar.

Refer to this page for Apple Support features ➔ Contact - Official Apple Support

Select from the presented options until you find a solution for your issue, or see if there is a chat or phone call contact method offered lower on the page under “Get more help” (you sometimes have to narrow down the options multiple times before this is shown). If you do not see your issue, keep experimenting with any series of selections until you reach one that offers a chat session or a telephone call and get the representative to redirect you.

This support article has various country telephone numbers for contacting Apple for support and service ➔ Contact Apple Support - Apple Support For some countries look under “Other” listing at the end of the list. Not every country has telephone support, and phone numbers may only work when calling from the same country.

If an app or feature on your device is not working, not appearing, or is restricted (grayed out), a frequent reason is it may have been disabled using Screen Time, or by a technology administrator if you are using a device owned by an employer or educational institution.

- Read this support article If your Apple ID or other options are greyed out in Settings —> If your Apple Account is grayed out in Settings, or you can't sign out - Apple Support

Tap your Settings app > Screen Time > Content & Privacy Restrictions > scroll to Accounts > tap Allow Changes and turn on.

- If the device is managed (check: Settings > General > VPN (or Profiles & Device Management), contact the technology department of the organization that is doing the managing.

● Situation where a VPN was preventing action —> Unable to sign out of my Apple ID on my i… - Apple Community

To test for this, remove the VPN entirely, don’t just turn it off.