How are you searching? I was able to search for it just fine on lemmy.world by going to the magnifying glass in the top right (by your username) and searching https://kbin.social/m/japonic.
Thanks for checking. I was searching on mobile and tried on different Lemmy instances, all the different ways detailed in my post above. I wonder if just sharing the link here (on an already federated magazine) helped or if you searching as a user helped get it to show up (I admit I don't have a Lemmy account).
Weird in any case, but glad it's working now, thank you!