PayPal account blocking after adding credit card?

Once PayPal notices (and this happens at some point, sometimes even after years) that you have opened the account with incorrect data as a minor, it will and will remain locked. Even if you’re 18 now and prove your right identity.

My tip would be:

Remove bank account/cards and phone number from the account and then close the PayPal account. Then, with another e-mail address, open a new account with correct data, exactly as indicated on the ID including all first names and correct date of birth. Add bank account, cards, phone number again. If there is a lock, you can prove your identity and unblock the account via customer support. With your current account, this would not go because PayPal basically does not unlock any accounts that violated the terms of use.

Of course, you can also come up with this and contact customer service directly after creating the new account and simply explain the thing and identify you in advance. That would be the cleanest solution. You are far from the only one who has registered as a minor. That’s what the employees know and that’s why they don’t take their heads off.