Given Middle Earth is an artificial world that was sung into existence by beings of vast power, I’m not sure plate tectonics had all that much to do with directing its formation.

The continent hosted a war between gods that destroyed a continent, who knows how that affected the geography of the neighbouring lands.

The One Ring also didn't have unlimited power. Gothmog, Sauron's master, did something similar with his own spirit, except he was so powerful he used the entirety of Middle-Earth as his "ring" instead. It's why the elves can't stay on Middle-Earth without waning.