alright, so it’s been heavily implied by lore multiple times that khaenri’ah is in the abyss or at the very least intimately tied to it ( bloodstained chivalry set, the pale princess ) and that kaeya was born in khaenri’ah. the thing is, abyssal creatures such as abyss mages, samachurls, and now, abyss heralds don’t need the blessings of celestia to wield the elements. it made me think that, for a khaenri’ahn ( confirmed to be a very prosperous and advanced civilisation ) born in the abyss, someone who isn’t entirely human — i think technically that kaeya should have the ability to wield his element without his vision. and so, because idc what canon thinks, i’m making that true.
much like magic is focused through a wand, the ability to wield an element is focused through a vision. when kaeya was found near a secluded nook along the path of the dawn winery, drenched from the storm around them, he was covered in ice particles. not only that, but the worker that he’d assaulted out of sheer panic at being approached by a stranger, had been stabbed by an icicle. although, kaeya barely remembers that night, had intentionally blocked it out of his mind actually. kaeya is unaware that he’s used cryo prior to his vision, but, not detailing them yet as i want to sit on this idea more, he has been in dangerous situations where he has unintentionally coaxed forth a cryo shield ( you might be familiar with this, it’s the same one you have to break down to get to the squishy abyss mage inside ) otherwise known as “ frozen kiss “ which is kaeya’s fourth constellation. kaeya has applied cryo to his enemies before, numbing them, slowing down their stamina, making their blood freeze, just by touching them before, also without noticing. he’s also left ice particles behind from things he’s touched before, often when he is trying very hard to keep his composure. kaeya’s resistance to the cold, also, has been a natural part of him since birth, although he attributed that to living in khaenri’ah for his early childhood, a sunless land.
kaeya has had multiple instances of using his cryo abilities accidentally throughout his upbringing, but chalked any weird happenstance up to coincidence because of his conditioning during his assimilation into mond / teyvat culture that everything coming from the abyss is bad and evil. and so, when these abilities started to manifest, a part of him wanted to remain ignorant ( after all, according to mond’s psuedo christian religious aspects, if we put this in the allegory of the apple, then to be ignorant is to be blissful, and to understand the truth of the world, that makes you a sinner, yes ? kaeya has said that khaenri’ah is full of sinners due the to the nation’s thirst for power and knowledge, y’know, in addition to his own self hatred coaxed by being raised in a foreign land that damns his own. ) a part of kaeya didn’t want to believe that he could wield cryo until he’d been “ gifted “ his vision, and even then it angered him, especially the way he received it.
kaeya views his vision as a means for the gods, for the tsaritsa, for celestia to control him. but, it’s a lot more complicated than that. when he stopped trying to destroy his own vision, out of rage first ( rage that the vision had appeared, symbolically aligned him with the fatui that had indirectly killed his father ) and then out of curiosity, he decided to use the ability as a means to an end, to reach his own goals faster. yes, he uses the vision and the privilege afforded a vision user in the world of teyvat, but he leaves it behind when he goes to domains on his own. why ? because it’s an insult to the khaenri’ahns and abyssal creatures down there … he can still wield cryo without it, but he still mentally attributes this to having a vision, no matter how far away it is. that’s not the truth.
kaeya is abyssal, he was born in the abyss, even if he’s still human. and he’s still coming to terms with it.
tldr ; there’s a reason that kaeya’s vision is visibly different from other mondstadt users, he doesn’t need it to use cryo. abyssal creatures don’t need permission from celestia to use their powers.