Some links you may find useful

  (Edited: )

I took a quick glance at the sites you mentioned and I guess I have few recommendations

Probably the number 1 source for SC2 is - it includes pretty much all of the important news, as well as some guides (though I'm not sure how active is the builds part of it since I don't really read that too often). It also has a list of live events, shows and streams on the sidebar.

The other popular news place is r/starcraft. Though if you're looking for strategy advice, you probably want to look at race specific subreddits such as r/allthingszerg.

There are also sites like Spawning Tool if you're looking for more builds/guides, though keep in mind that big patch just kicked in, so things are being figured out right now.

In terms of guides etc. I think other than that it's mostly single content creators making stuff, I'm not sure.