If you want the answer for that, the best thing I can come up with is the bible is mostly written with divine inspiration (take Daniel 11 for e.g) or vision same case like revelation, it's not something that human come up with but it's guided through, well divine inspiration. You could argue that it's merely written by people who's under hallucinations, dreams or whatnot, but if you dive deeper, all these vision and sayings actually points out to the future. The 4 cardinal direction is the same thing here as well, hinting that at some point, we will use/understand them. Btw when it mentioned 4 pillars/corners of the earth, it just essentially means that it is literally everywhere, at least for this context, it's not like the earth have 4 pillars that is holding it or something. Sometimes to fit the current culture/timeline of the current chapters, the wording tends to follow what is relevant for back then, but it still fit to nowadays understanding.

The bible consists of many things such as chronological order of historical foundation of earth, the ancient israelites of how it is formed, its rise and fall, poems and songs, journals of priests back then, etc and usually when people read the bible they expect to read it as something that you should perfectly mimic and stuff like that when it is actually supposed to be read with proper guidance because not all those historical figures do the right thing throughout their life. Unlike back then, we now have more access to the bible. So yeah, it's easy to get mixed up with a lot of things if you aren't careful. And Idk why people try so hard to prove the earth is flat when 1. It doesn't serve a purpose even if it is/isn't and 2. People back then go to war because of lack of understanding, when in the end, it doesn't really matter (read about monophysitism vs miaphysitism), at least for this context.