Where I live almost no one has a credit card and I tried to use my IBAN but it didn't work. That's why I ask myself if it is even possible.
But Steam has agreements in many countries and allows the use of cards from those countries, they are considered local purchases. Can this be the case?
I live in Chile and for example, you can use a local debit card with steam, but the same debit card is not served in itch, because in itch it appears as an international purchase.
I make my comments based on what I have seen in Chile, it could be totally different in your country.
I don't know what country you live in.
The first thing would be to find out at your bank if they have any way of making international purchases.
Many banks give you a debit card, but it can only be used locally, however, many banks offer additional accounts or cards that can be used for international purchases, but you must apply.
EDIT: I'm not talking about a credit card, but a prepaid/debit card, but for international purchases.
Another option is to find out if PayPal has an agreement in your country that allows you to link your bank account with them, that way, you can buy using PayPal, but paying with your normal bank account.