Symfony 6 populate Dropdown with Dynamic entities

I have a CreditCard entity, on form screen there is a dropdown with user’s Bank entities and I want to fill BankAccount dropdown according to selected bank dynamically, I have tried couple solutions from SO and added an event listener to my form but when I change the Bank dropdown I get “Integrity constraint violation: kart_adi (credit card name field on entity) cannot be null. I am using Symfony 6 with php 8.1.2