god mutations were just a concept in arcane adventures that featured mutations (step-up evolutions of magics, fire or light magic to flare magic for example) unique to only that magic (light magic to aether magic) but since AA died before mutations were a thing, nothing came of it
plant and steam magics- at least in AA/the seven seas- are mutations, i can recall discussing this topic with vetex and tech all the way back in 2020 to remaster an old mutation chart that you can refer to here 7 Seas Mutation Chart [2020], just keep in mind that this was years ago so i’m not sure if vetex’s mind has changed since
as for supermagics this is the first time I’ve ever heard of these so i have no idea as pristine said that could just be a supercurse user who has the power of multiple curses