Pay securely with an Android smartphone, completely without Google services: This is the plan being developed by the newly founded industry consortium led by the German Volla Systeme GmbH. It is an open-source alternative to Google Play Integrity. This proprietary interface decides on Android smartphones with Google Play services whether banking, government, or wallet apps are allowed to run on a smartphone.
For card (mastercard) nfc payments I use Curve pay on LineageOS with microG
I use it with GrapheneOS too. Perfect.
Does it need play and/or services?
Yes; but I’m not logged in to any Google accounts.
It also works with MicroG (although the GrapheneOS guys don’t recommended using that).
They rejected my application to open an account with them…
Yeah, I had trouble too but persisted and now it works brilliantly. I’m in the UK and it worked in Singapore, Australia and Japan.