I am quite new to the game and cannot seem to get the hang of the combat score system and how it influences my ranking up or down. Do I have to have a "good" combat score to get more plus points and less minus points?

Scoreboard down below (I am roocki). I usually play sage. In this case I have more kills, more assists and more plants then the players above me. Why is it that I my combat score is still way worse then compared to the others?

Happy to get some insights! Cheers!

​