Chromium yes. But firefox was shipped with the distro, so I am guessing it is not flatpak, but not sure.

Installed Aurora the other day (distro based on kinoite) and could not make my bank software run... It is a "local" (ie, only used by banks in my country) software only available for Ubuntu that requires a systemd service. Tried a lot and couldn't get it to work. The service started, but the browser accused it was not installed.

First time hearing of bravenewpipe so I don't know. You can check the git commits and releases though.

There is also PipePipe

Lol wut vibes

https://saladtheory.github.io/

I do the same plus a python script to automate the stowing. This plus konsave plus a script to install packages and it is a breeze to reinstall the OS