It sounds like you know more about ActivityPub than I do, but that seems right. My guess is that .ml and .world are so overloaded that there’s just a massive delay coming from them. It is kind of funny that, like you mentioned above, with my Lemmy instance I have almost perfect sync with Kbin servers but problems with Lemmy.
I’m hopeful that this is like Mastodon, where things calm down in a few weeks and there’s a smaller but more sustainable userbase.
I can’t even see this post on my selfhosted instance, so that’s fun.
With regard to #6, you apparently have to search for the URL of the Kbin magazine (e.g. https://kbin.social/m/RedditMigration) and then you can subscribe as normal from that point on.
And yeah, the discovery and comments thing is super annoying. There will be completely different conversations based on where you’re viewing the post, which kind of kills the idea of all these instances federating in the first place.
That being said, it appears to be feeds coming from lemmy.world and lemmy.ml that have the majority of the problems with comment/post sync. Unfortunately that’s the selfhosted community.
But… it does?