Thanks for your updates Marty, I’ll get them into the app. I just wanted to touch on one thing you wrote in your post, and that’s:
but I don’t consider e.g. /2019/01/ to be a “feed”,
Because it is a feed.
Your /year /year/month pages are archive pages and these are exactly what h-feeds are for. A feed is a collection of entries and this is a collection of entries. A good use-case for having them as feeds wanting to follow people for a year or month only.
I really don’t see any reason for it not to be a feed and I’d argue for the sake of implementing spec and having tools that ‘just work’, it should be a feed.