Gnome Software and Alternative Means of Software Acquisition

In other words, now that so much software is coming at us using distro-independent means that I am getting confused by bugs in Gnome Software and means to use non-distro software.
I enabled Gnome Software to understand flatpak and snap and I see that there are flatpak and snap commands in the CLI and I am studying those. However, in seeking a new RSS reader to replace the web-based Feedbin, I installed Gnome RSS Reader and Feedreader and I see them in Gnome Software but I can’t get rid of them, even using “apt purge”. There seems to be a Feedreader daemon that got installed and I don’t know what it is called but it is notifying me of new articles.
I like Fluent Reader, but it comes as an AppImage and it runs fine but I don’t know how to integrate it into my Menu and Favorites.

Does anyone have advice or a tutorial that can help me through this morass, tuned to PureOS or Debian? Thanks.

Not quite sure I understood entire post well but still looks like it is called org.gnome.FeedReader. Therefore please take a look if flatpak uninstall --delete-data org.gnome.FeedReader helps. Probably related link (current idea of mine) is mentioned here: How to install fractal next. As first step, to find/confirm both related applications please execute:

$ flatpak list
$ flatpak info org.gnome.FeedReader

All commands related link:

For CLI on how to install & run please see here:

Thank you for the help. Flatpak thinks that FeedReader is gone and there is nothing to uninstall. Gnome Software seems to have updated itself and it no longer lists FeedReader or Gnome Reader, but I still have a daemon downloading articles and sending me notifications.
Perhaps I can find a modern GUI replacement for Gnome Software that shows flatpak and snap options properly.