Mapping accurately is an incredibly time-intensive process.

A person or company that puts in the time and effort to accurately map an area, and sell the resulting product, deserves to get compensated for that time spent, in my opinion. And if someone comes in to take their work, copy it and sell it as their own, then that could justifiably be called copyright infringement or theft.

Just like how a painting of a church can be copyrighted (while the building is not), or how a dictionary can be copyrighted (while the words are not), a map can be copyrighted while the features that it depicts are not.

like wtf is a copyright for?!?

The copyright is for the time and effort spent to accurately map a region.

Like if two people happens to draw the same exact map, then what? Who gets to sue who? First come first serve? Literally does not make sense.

If they drew it independently, then there is no copyright infringement since there was no copying.
But it is worth noting that the odds that two people independently drawing the exact same map independently are in reality very slim. It is highly suspicious if someone starts selling what is effectively a copy of your map.

In practice such cases of copyright infringement will have to be taken to court, where the person having their copyright infringed needs to prove beyond reasonable doubt that their copyright was in fact infringed.
This is often difficult to do with maps.