Fae are restricted by magic laws. Lorian can’t force the apple into Mina’s mouth directly, she must take it willingly, or the spell won’t work. It’s ancient magic, god’s magic. The enchated apple trees are older than fae themselves. The spell that curses you to be unable to leave fey land is as old as first fae and gods. Even Lorian can’t break the laws, even if he plans exactly that. The fey would literally rule over death and life if laws didn’t bind them. They did, in the even of time, but jealous gods disliked it. So they gave them laws and limitations. The Devourer just created a beautiful race of vile creatures on his own image. He didn’t expect them to be that clever though.