Incidentally the Titan Keepers were once mentioned as the Pantheon of Order.
In otherwords the Titan Keepers were likely first then got their hands on the Titans.
Once Odyn(who is stated to have had Loken and Thorim as Sons which is not something one would believe if Khaz’goroth created the Titan Keepers) got his hands on Khaz’goroth he had all he needed to create more Pantheon of Order Members!
They probably aren’t called Titan Keepers because they are caretakers of Worlds sent by the Titans but most likely because they are Pantheon of Order Members who secure and keep the Titans for the sake of Order!