Just a note,
It was shown a lot of the recent threadiverse federation issues were/are being caused by Lemmy. Major Lemmy instances were/are intentionally or unintentionally (due to a bug in their platform), blocking inbound federation traffic from Kbin and Lotide. While allowing their own outbound to go through.
The jury is still out on if it was an oversight/issue with their latest release, or something more nefarious on the part of the devs with regards to competition.
I don’t thinks that’s accurate, Kbin has only co-existed for a few Lemmy versions. I’ve been on Kbin before the initial wave of new users, when the site had about 200 users, federation was fine. You may be thinking of when federation was deliberately broken by Ernest with the entire fediverse for about a week when he had to enable Cloudflare DDOS protection during the first surge of signups.
The specific issue here was highlighted by a Kbin user several days ago. They monitored the traffic back and forth and saw that inbound Kbin-bot requests were denied by Lemmy.ml after the latest upgrade. At the time of that post, Lemmy.world did not have the issues and it had not upgraded yet. I’m not sure if that issue has since been fixed in the code or not.