This is exactly it. I glance at All on Lemmy for maybe 2% of my time here, primarily to see if I can discover a new community that I didn’t previously know about to add to my collection.
But it’s true. The real Lemmy experience is in your subscribed communities.
I don’t see much talk of Lemmy on Reddit, but I’m primarily only on Reddit for a small handful of niche subreddits where no one talks about these things anyway.