I started out on kbin.social and I am now also trying lemmy.world. Is there an easy way to sync my community/magazine subscription between those two, or any two instances?
Other than just manually searching and subscribing to them again?
Sadly no, there's no migration option like we have on Mastodon, it's all manual here for now.
I've had to do it once to move away from Beehaw though and honestly it wasn't as bad as I expected, just open all your subs in a new tab and paste the new home instance into the url before the /c/ and refresh them all, that let me get most of them without copy pasting to search each one.
Ah right if it formats Kbin magazines differently from your end yeah you'd need to edit the URLs a bit more like you have done there. Migrating from one Lemmy instance to another, I just had to replace the "lemmy.world" (or in my case beehaw) bit with a new instance if you see what I mean so it wasn't too bad.
Sorry there's no better way, I hope you don't have as many subs as I do lol.
I've seen some people make GreaseMonkey (or some other) scripts to migrate subscriptions. Maybe search for "script" here or on lemmy.ml. it was at least a week ago I've seen that.