A lot of people on iOS use smart invert as a system wide dark mode, as long as there isn’t a better solution. Smart invert inverts all colors except on images etc, if it’s correctly implemented by the developer.
I might be a possibility for bunq to utilize this function, maybe as an temporary solution.
The ‘only’ thing you have to do is set the property accessibilityIgnoresInvertColors to true on all the views that should not be inverted, such as images.