I like Feedbro (https://addons.mozilla.org/en-US/firefox/addon/feedbroreader/). It’s a Firefox add-on, so it should run on almost anything that runs Firefox.
I’m just not sure how they finance themselves, so maybe don’t use it if you are on some three-letter agency’s naughty list.
Huh, I haven’t thought of that.
Openly and well communicated, that could be a good monetization scheme for this kind of software.