What I do is simple once you have a power rankings started.
I have the teams ranked 1-32 with the teams starting the week with points in reverse order
1=32 points
2=31
3=30
....
31=2
32=1
Then I award those points if you beat a team or subtract the ranking if you lose so....
#1 beats #30 then the #1 team adds 3 points while the #30 only subtracted 1 or vise versa if #30 beats #1 then #30 adds 32 points while #1 subtracts 30.
I then adjust based on win/lose record...+5 per win/-5 per lose and a tie is 0.
So an 8-4 team is +20, 10-2 team is +40 and a 1-9 team is -40
Then I take each teams ranking in total offense and total defense (1-32 each) add them and subtract from a base 66.
So a team with the #1 offense and #1 defense would be awarded 64 points while a team ranked 16th on both offense and defense (32) gets 34 points etc
Finally I adjust each teams points with each teams turnover margin...+10...+5...-5...-10 whatever.
Add it all up and elite teams will have over 100 points while winless teams will fall below zero into the negatives.
Example from my Quick and the dead league
https://fantasy-league.myfootballnow.com/forums/1/475?page=5#2396