Okay so this heavily depends on the possibility of a team's score being negative but something like

[(team 1 score + team 2 score)/(2 x winning team score)] x n

where n is the number of points awarded for the win/loss in this situation as previously outlined depending on the stage/tournament

Technically SQL would work for what you want, the issue being that database stuff can be expensive (in time and or money) to host/maintain. I think based on just what you've explained that you could do most of the math in excel/sheets, especially since it would allow you to track where/when team scores come from in a big table. You could then make nice graphics yourself with the resulting info/calculations