That's a great graphic!!!
In a way, it seems arbitrary to measure the height of a mountain from "sea level" up. The ocean is just the low surface areas that filled up with a little bit of water.
If measure from the actual "surface of the earth" even if it is underwater, the mountain from base to top of Mauna Kea is higher than Everest, though not as high as the Mariana Trench is deep. And the comparison to Olympus Mons on Mars shows that features on Earth are not the ultimate even in our solar system.
"...rising above the Red Planets frequent dust storms is the Olympus Mons -the tallest known volcano and mountain in our solar system. The central edifice of this shield volcano stands 27 kilometers ( 88,580 ft) high above the surface -or three times the elevation of Mount Everest above sea level and 2.6 times the height of Mauna Kea above its base. It is 550 km in width, flanked by steep cliffs, and has a caldera complex that is 85 km long, 60 km wide, and up to 3 km deep with six overlapping pit craters. Its outer edge is defined by an escarpment up to 6 km tall; unique among the shield volcanoes of the Red Planet..."