Peace the Guided one:
15:19 And the earth We have spread out (like a carpet); set thereon mountains firm and immovable; and produced therein all kinds of things in due balance.
20:53 He Who has, made for you the earth like a carpet spread out; has enabled you to go about therein by roads (and channels); and has sent down water from the sky.? With it have We produced diverse pairs of plants each separate from the others.
43:10 (Yea, the same that) has made for you the earth (like a carpet) spread out, and has made for you roads (and channels) therein, in order that ye may find guidance (on the way);
50:7 And the earth- We have spread it out, and set thereon mountains standing firm, and produced therein every kind of beautiful growth (in pairs)
The Quran is correct in all that speaks about what we call the real world, scientific/observable Truths. That is the main reason that affirmed my belief that there is a creator who revealed those books, and that P. Mohammad could not have known that information unless the creator of all this gave it to him.
The translation, better without the parenthesis, is not that bad, but your interpretation is wrong. I think your confusion is because we call the matter in which we can walk earth, as well as the planet. You need only basic knowledge about geology, but only God can make you understand the idea,. See the new forming islands of Hawaii, or the Galapagos, you will see How God spreads the earth.
The planet is made of solid matter/earth surrounded by water, we still are not sure if lava flows out because the center is molten earth or because of the friction on the tectonic plates. From underneath the water God makes mountains/volcanoes grow, forming kind of mushroom shapes that when put together form continents. not that simple, but God willing you will get the Idea. the stem of the mushroom shape islands are the pegs that the Quran says prevent the earth/continents from moving. The Quran only contradicts the idea that the continents were a single piece of land in the beginning, idea that, makes no sense, but it is twisted and needed, because otherwise the dumb theory of evolution make no sense. Theory that claims that the continents float around the planet, constantly moving. That You spread whipped cream over a cake does not mean that the cake is flat. The Quran does not Say that the planet is flat, neither that it is spherical, those are interpretations of the corrupter. You do not need expensive tools, only go to a tall mountain or a building, and you will see the earth is spherical.
may God increase our knowledge and give us wisdom