Flat earthers use 1 Samuel 2:8 and Psalm 75:3 which mention the pillars of the earth, and how God has "set the world upon them." But this is poetic, meaning that God has created all things and established them.
Flat earthers use Job 28:24 and Psalm 48:10 which refer to the ends of the earth. But this is symbolic for a great distance or all people. Acts 13:47 says the Lord has commanded us to "bring [the message of] salvation "to the ends of the earth."
Flat earthers use Isaiah 11:12 and Revelation 7:1 which speak of the four corners of the earth. Still symbolism, referring to something happening in all directions: north, south, east, and west.
The Bible doesn't explicitly say the earth is flat or round, although it does allude to its spherical shape. Job 26:7 says that God hangs the earth on nothing, and Isaiah 40:22 says He sits above the circle of the earth. If you think the Bible says the earth is flat, you put that in the text. You did not pull that from the text. Flat earth cosmology is derived from paganism, not Christianity.
Whatever you believe about the shape of the earth, it doesn't have any bearing on your salvation. "Believe in the Lord Jesus, and you will be saved" (Acts 16:31). Nonetheless, the Bible says avoid irreverent, silly myths. Have nothing to do with foolish, ignorant controversies, when we understand the text.