Ahh I understand better now, alls well that ends well.
Most banking apps will work, they just require sandboxed Play Services to be present in the main.
There is a resource at https://privsec.dev/posts/android/banking-applications-compatibility-with-grapheneos/
However would advise also checking/searching the issue tracker too for more updates that may not be listed at present. https://github.com/PrivSec-dev/banking-apps-compat-report/issues
NFC Pay is available but as you say not GPay, a lot of French banking apps for example implement their own version, as well as European users of Curve where GPay isn't available have access to Curve Pay. Stocard used to also implement it via their own top up virtual card but they deprecated the feature.
GPay works every now and then but Google soon does something to the back end that breaks it again.
Regards zaps yeah unfortunately the project doesn't have lightning and I am not here to profit from the dev teams work. There are crypto donation methods available at grapheneos.org/donate though. Lightning is on the roadmap but having just incorporated as a non profit until donation channels have all migrated it won't be set up for the moment.
Glad we got to connect though.