DIKOO Picture Hanging Mark Hole and Leveling Kit for Frame Mural Hanging - with Mini Bubble Level Used for Mark Nail Hole Frames etc Location Tool Set

I have keyhole makers for stuff just like this. https://a.co/d/06ljd4pt I tape the wall with painters tape in the approximate area. Mark the middle on the mirror and the wall. Then I hold it up, line up the middle lines and press the mark. Then make the two marks level.