I love my Graphene setup! I cannot tell you whether your banking app specifically would work, but a few comments on my experience, in case it is of interest:

I never used my banking app on my phone prior to Graphene either, so I have never bothered trying to install it. I bank on my laptop. When I installed Graphene I also stopped using Google Pay. I just carry a card with me in a holder in my phone case, same thing really. Revolut I do use on my phone, and it works fine on Graphene.

MitID I assumed would not work, so I never tried. I ordered a Kodeviser, and for me it has not been an issue to not have the app, once I got used to it.

The only apps I had any trouble with were MobilePay and Rejsekortet at first. Both work fine now, after some minor tweaks to settings.

So all in all, there's a few slightly more manual things, like using a physical payment card and a Kodeviser, but I am happy with that tradeoff. The actual installation and setup up Graphene was super easy as well, so you could always give it a shot, and revert if you find it doesn't work for you.