Do you mean the pretending to be a pixel part? Just click on the gear icon in Aurora and you should see an option to do that. You select the device and then Aurora restarts and you can try if the app can be installed afterwards. If not try a different device. I only had one sparkasse app that absolutely refused to be downloaded from anywhere else but Google play. For banking apps in general you’ll find a list of working apps somewhere on the e/os forum.
They sell the fairphone5 with e/os preinstalled, and there is an official build for fp5 including install guide (which is what I followed, just make sure to use official and not community build as you can’t relock the boot loader with the community versions). https://doc.e.foundation/devices/FP5/install