Itch could implement MyBank as a payment method for Europe (and others that are not US based).
Of course the main problem is these payment method are not international.
But even if itch implement multiple national payment method to avoid mastercard/visa for nsfw games, I'm not sure it will matter since mastercard/visa can still bully any platform even if they are not used just by nsfw titles...
if will of course be awesome if itch could decide to just implement all national payment method and say "go fuck yourself" to mastercard and visa but I don't think most users will actually be happy about it (and people from the US would still be excluded unless there is an alternative in US to mastercard/visa and other stupid payment method that want to censor games).