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 use iCard. It’s not open source but it’s not Google or Apple, which is the most important.
Icard is actuality the only alternative that can register as a contactless nfc payment that not relying on google/Apple wallet and its perfectly safe. It’s an actual bank in Bulgaria and is eu regulated and PCI certified
Not Foss. Kinda of a privacy nightmare as you need to verify your identity and location with actual documents but as already said its not google and is a solid option if you are degoogled.
You can’t do any kind of banking without extensive privacy invasion these days. It’s called KYC: https://en.wikipedia.org/wiki/Know_your_customer
Even if you found a bank with an open-source wallet application (you won’t), they would still ask you your ID, your income, what you spend on, your mortgage, the list of countries you have accounts in, how much on each account, the size and color of your underwear, you’re wife’s shoe size etc etc.
Unless you find an employer that pays you in cash (you won’t), you can’t do anything private with your money anymore. Welcome to the 21st century dystopia.
