uhhhhhhhhhh. pantheism? multi-polytheism? your guess is as good as mine.
i’m of the persuasion that other pantheons certainly exist, but i only worship the Greek pantheon so that’s qualified as polytheism. but… i honestly don’t know what to call worshiping more than one pantheon. followers?
The belief that all gods exist is called omnitheism- perhaps that’s closer to what you may be looking for?