JakobRookie
Hi, so similar experience here. I talked to PayPal multiple Times. I tried adding a NL IBAN, a BE IBAN, a FR IBAN, a HR IBAN and a Polish IBAN. Everytime I had an error. I called PayPal multiple Times. All Accounts where Blacklistet, the support agent told me. But this was not possible because those IBANs where all created for the purpose of testing this.
My conclusion: PayPal hates Fintech Banks or just discriminates people based on their Bank Account location. This is illegal in the EU since 2017.
A few agents told me that they removed the option of adding non german bank accounts for germans because of security reasons. This is still illegal. But as long as nobody complains nothing will change. There are institution which get in court for you.
Here are a few links where you can report IBAN-discrimination:
https://www.acceptmyiban.org/report_it
https://www.wettbewerbszentrale.de/de/beschwerdestelle/sepabeschwerdeformular/ (More for Germany)