Do you have an idea? Whether AlternativeTo nor OpenSourceAlternativeTo got an answer.
EDIT: I should have had added, that I was not looking for the financial aspects of the app, but I was looking for a possibility to store tickets and cards: Catima offers at least somewhat, what I was looking for.
I have looked around, myself, but not found a FOSS alternative. There are typically compliance issues like PCI DSS for certain banks that prevent trust and cooperation from those banks outside a larger entity like Google, Apple, etc.
Aside smart phones, Flipper Zero can clone some cards sucessfully. But that’s an entirely different device, not an app for a phone. Best of luck!
Also, if the Flipper Zero can clone your bank’s card, you should probably switch to another bank.
It’s a neat tool, and it can definitely do a lot, but it’s not magic, and it can’t emulate decent cards with proper security. If your bank card doesn’t have that, that’s… an issue.