itch.io

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.

the fastest way to fix this is by using online credit card, just move some money to that card and you should be able to do anything.