I'm not entirely sure why this is a problem. Nothing's stopping you from using f-droid as an app source as well as some other store - it doesn't need to cover every use case. It's already a viable alternative for apps which can't go on the Play Store due to Google's policies, like AdAway, NewPipe and Termux.

The fact there's no freedom respecting bank applications is a problem on its own, though. I will continue avoiding them until there is...