I don't think you're supposed to run anaconda-navigator as root.
You'll want to make sure that you have installed the application as a normal user and not as root.
So don't prefix the command to run the installer with sudo but just run it with your current user's permissions.
Once you're installed, try activating the Anaconda virtual environment before and ...
You have to add remotes separately for user and system installations.
This same thing caused me a bit of confusion.
The error message you received indicates that you probably just need to set up a system remote. To add Flathub as a system remote you would use the following command.
$ sudo flatpak remote-add --if-not-exists --system flathub \