Since a few years ago, the ECB is already looking into the possibilities for implementing a digital euro as another way of paying across the entire Eurozone. The phrase "digital euro" has been kind of a political boogeyman because of the privacy concerns (fair) and implications that the physical euro might disappear (less fair, the right to be able to use it as legal tender is enshrined in the EU treaties and that can't be changed without everyone agreeing to it), but the base idea is to create a public infrastructure that would do what payment processors and credit card companies are doing for a hefty fee right now. Which, to me, sounds like a great answer to this problem.