I'm subscribed to 50+ communities, so I won't list them all here. A lot of my interests are relatively niche (stuff like Linux/FOSS, DIY, bicycling/urbanism, etc.) so it isn't that surprising that some of the related communities seem to be averaging between a post a week and a post a day so far, since Lemmy as a whole isn't all that big yet. (It could also be that I haven't found the most popular community for a given topic yet, especially if it's on a different Lemmy instance.)

My subscribed feed being overly dominated by c/politics, c/world and c/technology (the communities I'm subscribed to that do have lots of content) might be part of the problem too.

My RSS engine

You wouldn't happen to have a Pastbin or Gist or something about it, would you? I'm curious about how to set up a similar thing for myself.