Zelda's growth and unlocking her powers
During the game, whenever you used her special attack, she says "I will defend Hyrule. Any way I can." but once her power awakens, it changes to "I will fight for Hyrule. Every way I can." This may seem like a small change, but it shows her growth from uncertainty and simply fighting because she couldn't back down, defending Hyrule any way she could because she wasn't sure she could do anything at all, to realizing that she can do something once she's unlocked her powers and realizing she can use her full potential and nothing is holding her back any more.
Nature of Terrako and Zelda’s abilities
How does Terrako send the New Champions back to the past when at the end he’s been reduced to a single screw? For that matter, how was a child, even a genius prodigy like Zelda, able to build a time machine? The answer is there, but subtly alluded to.Whenever Terrako does something highly significant, a curious bluish-white glow appears around him. It’s seen when he first activates, when he summons the Champions, when he stumbles back to life for the moments before his sacrifice, and when his screw sends the time travelers back to their own world.
What do all these events have in common? They correlate with Zelda displaying her sacred powers or high emotions. He activates in the first scene where Zelda first uses her power at Fort Hateno, he summons the New Champions when she’s expressing grief over the Calamity’s conquest, he reactivates despite being smashed when she uses her power to protect Link from Ganon, and he sends the travelers back when Zelda feels at peace thanks to their victory.
It’s likely then that Terrako’s powers aren’t as simple as mechanical functions, they’re expressions of Zelda’s will. Zelda initially had trouble using her sacred power, but it seems that her aptitude with technology allowed it to serve as a catalyst for her magic. So Terrako can open a time portal at the end even when he’s just a screw, because his pieces are more than just machine parts, they channel Zelda’s will itself.
On that note, there’s one other place we see the strange blue-white effect in the story. It’s on the ancient shield, when King Rhoam sees it glowing and then it activates to save him from Guardians. Why did it activate then and not before? That was when Zelda was in distress from being made to abandon him. She wished for her father to be safe, and her will made it so.
