Hyperion is an ability so teleporting can only happen if that cooldown is over. You have very little to defend yourself with as the flag carrier.
You can easily be killed once you have the flag so magic and items is your main defense. I wouldn't say it's an unfair advantage unless someone is literally teleporting the entire way across the screen to the capture point.
People can use magic and items on you, or grapple you as you jump with the flag. You're also slow moving with the flag outside of jumping and teammates are not often there to defend you.
Hyperion simply gives you an escape but it doesn't give you an unfair advantage.
