Tap-to-pay is available on GrapheneOS in Europe. Your profile implies you're in the UK where Curve Pay is available. There are also banking apps in the EU with working tap-to-pay but we aren't sure if any of the UK banks provide it without Google Pay.

90% of banking apps do already work on GrapheneOS:

https://privsec.dev/posts/android/banking-applications-compa...

> If they worked on a dumbphone, I'd have a dumbphone.

A dumb phone won't provide any form of secure calls or texts. People should migrate away from carrier-based calls to the extent possible rather than towards it. A dumb phone is also entirely reliant on cellular instead of being able to use Wi-Fi instead.