The Wikipedia article on news agencies is pretty good: "Although there are many news agencies around the world, three global news agencies, Agence France-Presse (AFP), the Associated Press (AP), and Reuters have offices in most countries of the world, cover all areas of media, and provide the majority of international news printed by the world's newspapers." Scroll down and you'll also find a list of some smaller news agencies, which tend to focus on local news.
Thunderbird mostly solves this since it has a built-in browser and uBlock.
Agreed on 1) the lack of RSS feeds. Lemmy also has a problem that RSS feeds aren't federated, so commenting on new posts is very clunky.