Hello!
There were... many, MANY ways that Sauron could have been stopped from becoming a problem in the first place, or at least been a smaller one.
Elrond and Gandalf are probably some of the worst planners in existence (excluding Dumbledore, but wrong universe, and I'm not that mean), and a hamster would have done a better job.
So here are some rather simpler ways to deal with a rogue Maia and his favorite piece of jewelry if you ever find yourself in this particular sort of pickle.