For reddit you can get a feed for the top posts only, and for HN you can set a score threshold. I even follow newsletters over rss (killthenewsletter), which if you subscribe to some daily digests you get exposed to stories from a variety of sources on many topics. I can still run through like 250 headlines in about 30 minutes, reading or saving what I like to pocket and skimming over the rest. There is definitely set up and optimization with RSS, getting the right mix of feeds that you want, but I don't see any targeted posts or advertising when I browse the internet now.

Its also really good for following journal articles in my field. Pubmed has active search RSS, for instance, and every journal pushes their new articles to RSS.