Sure, there are vids of Fed twisting one for an ace up the middle around a foot higher than head high.
There is a vid of a amateur twisting one about 8' high, got returned with a lob, and lost the point.
But those serves are abberations. Hit something on the court.
You cannot depend on a twist serve going 7' high at the baseline of your opponent because any short serve bounces lower, while anything slightly long get's called OUT. The landing spot is merely 9" for the highest bounce, and you can't serve there every time....as you well know.