NFC payments works, any bank / neobank app with their own independent NFC gateway will work, I have at least 3 bank apps that work with GrapheneOS.
Problem with this approach is that is very country limited and you need to stick with that bank whether or not their card is the best for your personal needs.
The only service to my knowledge that is close to a universal card gateway like Google Wallet is CurvePay. But they won't activate it for GrapheneOS unless we lobby them into realizing that there is a good niche business in supporting this OS.