The Bible doesn’t flatly say (pardon the pun) that the Earth is flat, but the implications are there for something vastly different than a ball holding a lot of water on it with “gravity” and spinning around in “outer space,” much less orbiting the sun.
I don’t necessarily believe it’s “flat,” per se, as I’m not sure what the actual shape is. But I do believe that the land and sea (what we refer to as “Earth”) are as vast and wide as the heavens are, because the Bible implies this by virtue of the fact that the heavens are sitting directly atop the Earth. The “earth” in the Bible only refers to land—never the entire world that we live in (to include Earth’s atmosphere and all the oceans, etc.). Earth’s atmosphere is apparently contained in the “heavens” mention, and the seas are just that: the seas, the deep, and the water under the Earth. Never in the Bible are the heavens (or even the “sky”) depicted as being present under the Earth—ONLY above it. Genesis chapter 1 reveals that in the Beginning, the Earth was submerged in the deep or in realms of water. God created a Firmament and used it to separate the waters above the Firmament from the waters beneath the Firmament; so above the Firmament (heavens) we have water, and beneath the Firmament we have water (seas, the deep, the abyss, etc.).
The Bible also clearly states (in Gen. 1) that the sun, moon, and stars were placed IN the Firmament—not beyond it, not off in some “outer space” that encapsulates this tiny little planet called “Earth” in all of its infinite vastness. That’s hogwash. What we call the “universe,” the Bible apparently refers to as the “world.” The “world” is not “planet Earth.” It is the composite (at least it appears to me so to be) of the heavens, the earth beneath them, and the waters beneath the earth/hell/Sheol, etc. (It gets confusing sometimes; I don’t profess to be an expert on the subject!) Hence, the sun, moon, and stars are revolving in their courses ABOVE the “plane”/land we live on called Earth and they are both confined to and hemmed in by the Firmament (that sits atop and meets with the boundaries of Earth).