Both for world-first and for the rest of us.
Halondrus mythic taking 300-450+ pulls for the four guilds that have gotten him, no one has Mythic Anduin down yet, and there's 3 more after him.
I'm also seeing guilds with Mythic Sylvanas experience not have a Heroic Anduin kill yet either, although presumably by the end of the week a lot more of those will go out.
And as someone that has pugged a great deal over the last fifteen years (and not raided in a guild at all in Shadowlands), I'm genuinely at a loss for how I'm gonna get past Anduin on Normal. I'm gonna try and stack a group probably next week when the second legendaries become available. I've heard tales of a few raiders that at least know of people that have gotten him in a pug, but literally haven't met anyone that's done it yet as of Wednesday of the third reset.
(Although the 25% nerf to the despair went live yesterday which should massively help.)
Trololol I've even heard LFR Halondrus is a real bear.