There are 3 leaderboards: official tracks, community tracks, and everything combined.
This might help:
You gain 100/sqrt(x) points per track, where x is your placement. Also, you only get points if you are in the top 800 on that track. Because of how the formula is written, the amount of points that you get per track increases exponentially as your placement goes down. One top 20 and that’s 25+ points.