Not just lopsided but limited. Depending on the sample period, we could be talking about as few as three or four opponents over 16 baseball games. An NFL team is always going to play 13 different teams in their 16 game schedule.
Even the NFL team with the weakest schedule is facing enough variety of opponents that their record isn't all that fraudulent or misleading.
To your point, per DVOA, the biggest difference between non-adjusted and adjusted is for OAK & PIT, which are just over a 5% difference between their ratings after adjustment (adjusted DVOA is higher than without adjustments), indicating strong opponents. In the opposite direction, it's IND at negative 7%, then HOU & CAR around negative 5.5%.
OAK played KC & LAC twice, plus BAL & PIT & LAR.
PIT played KC, LAC, BAL twice, NO & NE
IND played the NFC East & AFC East, plus their own division twice, plus OAK & CIN
HOU is the same as IND's schedule, except add Broncos & Browns
CAR... I'm bored now
Edit: My point is those aren't huge differences for the biggest outliers.