This 3rd party app in question ( mobilt bankid) is also used to access everything in Sweden ( taxes, banks, social security applications .. )
It's a proprietary product that's not publicly available, and yet it's required for many governmental services. Obviously, it's a recipe for disaster.
For example, when Swedbank found out that I use some service at another company, they closed my access to BankID and told me that I either move that engagement to them or ask the other company (which isn't part of the BankID oligopoly) to somehow get BankID.
Even worse, there are some stories about people losing access to BankID for political opinions. That's China level of repression.