O. Selaquet Unfortunately, there's a reason the bunq app hasn't been optimised for the XS Max and XR resolutions yet. To support those resolutions, the app must be build with Apple's iOS 12 SDK / Xcode 10 tools. We would gladly do that of course, but - and here's the unfortunate part - there currently is a bug in Xcode 10 that would make the app crash on iOS 9 and iOS 10 :-( Apple is aware of this issue, so we hope they'll fix it soon.
In short: we're waiting on Apple to fix a bug in iOS tooling that would allow us to build the app optimised for XS Max / XR resolutions and also not crash on earlier iOS version.