I think multi-reddits can be great, as you can isolate yourself from the mess of r/all, but unfortunately the comments sections on the subreddits I'm interested in are nowhere near parity with HN. Furthermore, the subreddits carry a lot of noise submissions that I feel aren't as strongly represented on the the front pages of HN.
Oddly, I have found YouTube has taken an increasingly large portion of my internet time. There are a ton of really informative, good quality education videos being pushed onto YT today, for example 3Blue1Brown's math content comes to mind . However, the comments sections for most videos is maybe only millimeters above being worthless at best, and detracting on average.