Hi there Daniel,
From what we can tell, you're unable to download apps in the App Store on your iPhone because you're having difficulty updating the billing address for your payment method. We're glad you're here, and we can help.
To start, " If there's an issue with the billing address or expiration date, tap or click the payment method, then update the payment information. If you change your payment method, use a valid payment method in your country or region with money available on it." Have a look at this support article to learn more:
If your payment method is declined in the App Store or iTunes Store
Next, "Make sure that the billing address for your payment method matches the billing address for your Apple ID. In some cases, you might need to call your bank or financial institution to authorize international or online purchases. You might also need to confirm that the mobile number associated with your payment method is correct." This link provides more information:
Payment methods that you can use with your Apple ID
Also, "If you can't edit your payment information, try updating to the latest version of iOS or iPadOS or macOS. If you have subscriptions, have an unpaid balance, or share purchases with your Family Sharing group, you can't remove all payment information." Learn more here:
Change, add, or remove Apple ID payment methods
If that doesn't seem to help, you'll want to connect with the Apple ID support team for more assistance. Get started using this link:
Contact Apple for help with Apple ID account security
Cheers.