As you have 25 accounts available there should be no issue.
So if you don't want to save money anymore you can close the account (or leave it as is for a later opportunity) and use another account as your normal one. There might be an issue if you love your account number (IBAN) that much that you want to keep it :)
But to a savings account you can transfer money from outside bunq and you can link your cards to this account as well.