Are the tracks in this game randomized? And if not, is there a certain track to submit runs for?

The tracks are randomized. The entire point is to try and find the map that is the shortest and race well on it.

well, as per what i have as my experience, only one track is common among the wr, which is like 20 seconds with no mistakes

As of recent update we will be adding a new category titled ( Single Maps ) this will consist of different seeds that all players can race on giving a even and fair racing experience.