edited...
Problem with trying to get through the SEC is that someone has to lose, and by seasons end, there will always be teams that are really good nationally against most anyone (hence being winningest conference in bowl games since 1998), but get relegated to the bottom half of the SEC by attrition. I relaize all confrences have good teams at the bottom by attrition, but the SEC does it better OOC than anyone else. This is P5 to P5 results from 1998-2021 season (regular season OOC + Bowl Games):
ACC 241-296 (537 games) .449
B12 198-192 (390 games) .508
B1G 226-229 (455 games) .497
P12 181-166 (347 games) .522
SEC 278-216 (494 games) .563
Note: It only includes P5 opponent results. No G5 or FCS games included. This is purely P5 head to head results (conference games excluded). I find it interesting that with all the annual talk about the weakness of the ACC, and the fluff for the B1G, they are essentially equally bad. The B1G has only begun to spearate ahead of the ACC since the 2017 season in OOC performance.