The reason this deck works so well is that Magnezone is extremely versatile and it can fit in any deck regardless of the main type, which holds true for Mew Ex and Yanmega Ex as well
If you look in the art, you'll see all sorts of things stuck to it, weapons of former creatures that fought it, a person that formerly fought in its armor, horseshoes (it was the set's expansion symbol), the power/toughness box and even the corner of its own art
Instead, its a complex and, honestly, kind of ridiculous process involving burning cards, cooldown periods, and a new currency
Its second attack, Obsidian, is even stronger because it can thoroughly disrupt the bench setup of other Stage 2 decks
In the meantime, enjoy Ikoria: Lair of Behemoths previewsit should be a monstrous time
Oh, and this strategy may also help you uncover newly listed copies of a bad Reserved List card that already spiked