All I say is that it’s not FOSS in the strict sense.
FOSS is a standardized term. As the Free Software Foundation defines it:
Free and open-source software (FOSS) is software available under a license that gives users the right to use, share, modify, and distribute the software – modified or not – to everyone and provides the means to exercise those rights using the software’s source code.
You are not granted right to modify or distribute Bitwarden. You can inspect and use that to build your own. That is what Vaultwarden does.
Not if you are being strict with the definition of FOSS.
That means you want one browser to be not flatpak, in most distros the default is Firefox, but it’s up to you to change.
Why people bother with any corporate software when it really don’t provide much more than completely FOSS alternatives
I figured you have to layer the browser on the system. The KeePassXC can stay flatpak. That’s how it worked for me. You always want to have one browser layered, anyways.