Hacker News Reader

I like the idea of graphene, but I worry my banking / brokerage apps wouldn't work anymore and that'd be a deal breaker

The Graphene community maintains a list of compatible banking apps.

Another possibility is to keep an old/cheap, stock Android phone at home with WiFi only for apps like this.

Doesn’t that defeat the point of using an app at all? Use a computer at that point.

No, because some apps are mobile only, and only work on phones "certified" by Google or Apple.

If you need mobile check deposit, you can only do that from a mobile device.