Hello there @SpirantCrayon22,
I apologise for any confusion that may have been caused. Allow me to take a closer look at this, and I'll do my best to clear up any confusion about the Divine upgrades.
I'm aware that Animus Store items and Prime Gaming items (such as Bone-Maul and Carolingian Pike/Shield) are automatically upgraded to Divine quality upon loading up the game following Dawn of Ragnarok's release.
Additionally, as shared by @bielik01, some items can only be upgraded to Divine quality when in Svartalfheim. I checked in my own game, and you should be able to upgrade Mjolnir and Gungnir to Divine quality here.
Regarding the other items you've listed (such as Algurnir and the rest of the Twilight Pack), I'm not entirely sure on what dictates whether a piece of gear is eligible for a free upgrade, or requires resources.
I'll reach out to our dedicated teams to see if we can get more clarification on what items are upgraded automatically, which items can be upgraded for free (such as Algurnir), and which items will require resources to upgrade. Once we have any new information to share, we'll let you know within this thread.
Thanks!