Rankings of the NFL's 4 conference championship teams the last 5 years.
2017
Jax: #5 points off, #6 yds off, #2 points def, #2 yds def
NE: #2 points off, #1 yds off, #5 points def, #29 yds def
Phi: #3 points off, #7 yds off, #4 points def, #4 yds def
Min: #10 points off, #11 yds off, #1 points def, #1 yds def
2018
KC: #1 points off, #1 yds off, #24 points def, #31 yds def
NE: #4 points off, #5 yds off, #7 points def, #21 yds def
LAR: #2 points off, #2 yds off, #20 points def, #19 yds def
NO: #3 points off, #8 yds off, #14 points def, #14 yds def
2019
KC: #5 points off, #6 yds off, #7 points def, #17 yds def
Ten: #10 points off, #12 yds off, #12 points def, #21 yds def
SF: #2 points off, #4 yds off, #8 points def, #2 yds def
GB: #15 points off, #18 yds off, #9 points def, #18 yds def
2020
KC: #6 points off, #1 yds off, #10 points def, #16 yds def
Buf: #2 points off, #2 yds off, #16 points def, #14 yds def
TB: #3 points off, #7 yds off, #8 points def, #6 yds def
GB: #1 points off, #5 yds off, #13 points def, #9 yds def
2021
KC: #4 points off, #3 yds off, #8 points def, #27 yds def
Cin: #7 points off, #13 yds off, #17 points def, #18 yds def
SF: #13 points off, #7 yds off, #9 points def, #3 yds def
LAR: #7 points off, #9 yds off, #15 points def, #17 yds def
Average ranking
Points off: 5.3
Yards off: 6.4
Points def: 10.5
Yards def: 14.5
Number of top 5 ranked units
Points off: 12/20 (60.0%)
Yards off: 8/20 (40.0%)
Points def: 4/20 (20.0%)
Yards def: 5/20 (25.0%)
Super Bowl champ average ranking
Points off: 3.8
Yards off: 6.3
Points def: 6.5
Yards def: 12.0
Super Bowl champ top ranking (of the four teams in the CC games)
Points off: 0
Yards off: 0
Points def: 3
Yards def: 1
That last data set I need to explain a little more. I looked at the four teams in the conference championship games (we can't count this year because we're looking at SB winners, and obviously we aren't there yet with 2021). Of the four points offense rankings for the four finalists, which one had the highest ranking in that category, and then how many times did the team with the highest ranking (of the four teams) actually win the Super Bowl? So it's interesting that none of the teams with the highest points or yardage offense rankings (of the four remaining teams each year) won the Super Bowl, but three out of four times the team with the highest ranked point defense, and one team with the highest ranked yardage defense won the Super Bowl.
Seen another way, here's the rankings - AMONG THE FOUR REMAINING TEAMS - of the SB winners:
2017 (Phi): 2nd, 3rd, 3rd, 3rd = avg off rank: 5.0; avg def rank: 4.0
2018 (NE): 3rd, 3rd, 1st, 3rd = avg off rank: 4.5; avg def rank: 14.0
2019 (KC): 2nd, 2nd, 1st, 2nd = avg off rank: 5.5; avg def rank: 12.0
2020 (TB): 3rd, 4th, 1st, 1st = avg off rank: 5.0; avg def rank: 7.0
So from this small sample, is it more important to have a great offense or a great defense in the modern NFL?