I have a special case problem, that I would like to ask for help for.
I have so far been using a Pixel4a running CalyxOS but decided to try out GrapheneOS instead. GrapheneOS is also installed on a Pixel4a. I have a problem with one App, MoblePay, which is a Danish payment app. This app i right now running fine on the Calyx phone, but I would like to copy/transfer it to the GrapheneOS phone with all userdata. On stock Android or if I had a google account, this is straight forward, but I'm less sure on how to do this on GrapheneOS.
Does anyone know how to transfer an App to the GrapheneOS phone, like described?
The reason I'm not just reinstalling the app, and setting it up again, is that the App is a slightly older version and If I update the App or reinstall it on a new phone, the App will force me to Identify my self again requiring a Danish Digital ID, which I do not have and do not want. In fact any change in the app or the userdata, will force this. When I installed the App, I could identify myself using other means, but the Danish State has forced both banks, MobilePay and many other organizations to only use and require a new Government Digital ID called MyID or MitID. A Digital ID that I do not want to use under any circumstances. Therefore I'm looking for a way to transfer the old app to the new phone exactly as it is. Actually I'm not even sure that transferring the app, if possible would be successful, but it is the only chance I have at keeping this app working and not loosing the ability to use this payment method.