MauiFeed is a .NET cross-platform Feed Reader, supporting RSS, Atom, and JSON feeds. Currently, I have MauiFeed working on Windows via WinUI with macOS and iOS versions under active development.
I do not intend MauiFeed to be the most feature complete Feed Reader available. Instead, I wanted to build an application that would both be useful to me and show the usefulness of dotnet as a cross-platform app development runtime. If you want those kinds of apps, check out FreshRss or NetNewsWire.