So our planet has a magnetic field generated by the motion of liquid iron alloy at the center of our planet. We can observe the field generated as it surrounds us and extends all the way into space, and you can follow the field lines (like you might have seen in school experiments with magnets) using a compass. Now the compass gives you a very specific direction, North-South, ending in two distinct points, which we call the magnetic poles. There is no way to create such a magnetic field on a flat disk.
Flat Earth theorists claim that the Earth is a ring magnet but that doesn't work. A ring magnet has a very specific magnetic field, where the direction of the magnetic field flips when you're inside the ring compared to when you are on the disk. Have you ever seen your compass suddenly point south while working north? And how would the magnetic field of such a ring be produced?
I mean, you want the center (Northpole) to be magnetic and you want the outer edges to be magnetic. They are not the same magnetic fields that are opposite of each other. One magnetic point (North) would be like a dot in the center and the other magnetic field would like an edge of a pizza crust. It's totally imbalanced.
Also, a compass would basically be a lie. There would be no true North on a flat Earth map. It would only be the center of the map.
The Bible mentions directions like North and stuff.
"And thy seed shall be as the dust of the earth, and thou shalt spread abroad to the west, and to the east, and to the north, and to the south: and in thee and in thy seed shall all the families of the earth be blessed." (Genesis 28:14).
But in the Flat Earth world, there technically is no such thing as called "North." It would be a lie. Your compass would be a lie. On a flat disc map there is no such thing as North really because it is actually the center of the map on your Earth and it is not truly North like on a round Earth (Which is the real world we live upon).
Source Used:
Here Are Five Ways You Personally Can Prove The Earth Isn't Flat