The goal isnt just to stop the opponent but to use their own heavy hitters to fund your winning play or a massive spell in your hand
A good card for this strategy would be a cEDH staple called Underworld Breach, which makes each nonland card in the user's graveyard have escape, with the escape cost being equal to that card's mana cost plus exiling three cards from the user's graveyard
Plus, there are plenty of cards in Lorcana that can enhance Princesses in many ways
The "morph five mana" rule says that if you attack with your morph creature into an opponent's morph creature, it will take a minimum of five mana for their morph to "eat" your morph (meaning it turns face up and destroys your creature without itself being destroyed)
Offering buffs, protection, life gain, and reanimation , Sword of Light and Shadow can be incredibly useful in a great many decks