Google Pay very likely needs more original Google APIs present. In that thread the microG author explains what would be necessary for a banking Apps to add Cards to Google Pay.
But even with this implemented, if Google Pay itself then can work in all circumstances, without Google Play and more? I don’t know
https://github.com/microg/GmsCore/issues/1245#issuecomment-734969823
- Banking apps sometimes use the TapAndPay API which allows them to add your bank account to Google Pay / Android Pay. This API is not yet implemented and probably causing issues here. As I guess one needs a bank account with that bank to try out, I can try to provide test builds, but debugging that way obviously is much harder.
so an adb logcat would clarify what Class the radobank App calls to add its Card etc, that microG could delegate if Google Pay is present