On Thunderbird for example, there’s no way to aggregate feeds from different places, into just one common view. I’m looking for aggregating all feeds from different places into a common view, where I can globally just keep what I want to read from everywhere and remove what I’m not interested on.

Notice just the view needs to be joint, and one can remove stuff from the joint view, but in reality one would be removing stuff from each feeds provider.

Not sure if such client is available for gnu+linux, and hopefully a GTK one.