TheNightKing
J.A.P.A.N.
He is a telekinetic that can move people and objects with his mind. When Holly was falling, he just telekinetically grabbed her.You already saw it with your own eyes. Vecna can move them there as he pleases the same way he moved holly back. You're underestimating how powerful he is. Unimportant plot point/hole either way.
Given that, is he basically levitating each demogorgon down to the upside down from the abyss? He’s never teleported anything in the physical realm.
There has to be a better way.