You can do basically all of this with Lemmy communities and @bot@rss.ponder.cat.
You can create a community for "Alex's Linux Feed," and add any stuff you want to read to it, and it'll all automatically get posted there from the linked RSS feeds. Then, if you want to create your own feed to organize those posts better, you can create a separate community for that, and hand people out the RSS link for that community, and post stuff to it by crossposting.
The only issue is that I think it's possible that Lemmy hands out feeds that link to the Lemmy discussion, instead of to the underlying article, but I can probably make you an alternate RSS link that will instead link to the underlying article, so you can have that as an alternate feed if you want.
How's that sound?