To get classic granted (which is by many margins harder to package and maintain correctly than a strict snap FWIW) your app needs to fit into one of the supported categories from:
(Which i doubt it does)
It should not actually be too hard to properly package such an app as strictly confined snap utilizing the existing snap interfaces though…
(Note also that since money is involved here, strict confinement would surely be the better choice from a security POV)
