I've been developing a modernized version of Aztec polytheism--called Teotlism, from a central concept of the historical Aztec religion--for my ASB ATL which could apply here, but it might not qualify as a "major world religion" depending on how we're defining that. computer troubles mean I can't copy-paste what I have on Teotlism from the Word document I have in, but the gist is that it's mostly the same except for the addition of a few new deities, including Dios, (from the Christian God, using the Spanish name; this actually has OTL precedent, as the Tlaxcallans adopted "Dios" into their pantheon as just another god when they allied with the Spanish) and the identification of a few indigenous deities with others--such as Tonatzin, a mother goddess, being identified with Mary based in part on the Virgin of Guadalupe, and, more originally, Quetzalcoatl is considered to be one and the same with Jesus by some Teotlists as well as Aztec Christians--and they actually no longer practice human sacrifice, which is replaced by animal sacrifice (also based on actual history) and blood sacrifice which, in personal prayer, often amounts to pricking one's finger and using that in the ritual.