I think it is completely legitimate to say that this is the weakest #1 seed, regardless of who it is, seen in the AFC in decades. No one's a clear favorite:
NE: Given their great defense and average starting field position, their offense is actually middle of the pack.
Bills: Josh Allen is arguably _the_ QB left in the AFC, but I don't see them surviving three playoff level defenses on the road.
Steelers: Their opponent gets the closest thing to a bye in the AFC. Terrible defense (especially vs. its salary), and Rodgers may die out there vs a real defense. They'll probably have the worst odds of all AFC playoff teams entering the postseason.
Jaguars: I can't believe these words are coming out of my mouth - the Jaguars are one of the strongest contenders left in the AFC. Their offense has been great recently, and their defense has been holding up.
Texans: Terrible offensive line, will get knocked off in the wildcard round. Whether their opposing QB / Oline survives intact is a real question.
Broncos: Their defense is fantastic. Their offense is crap until Nix can take advantage of gassed defenses in the 3rd and especially 4th quarter, and that's way less of a guarantee against the strong defenses left on this list.
Chargers: That Oline will not survive three playoff level defenses on the road.
So a lot boils down to seedings - both between Denver and NE for who gets the bye and home field, but also which wildcard gets the 5 seed and the rights to beat up Steelers...
... which is why this year is probably the best situation for NE or Denver to get the #1 seed, beat whomever takes out the Steelers in the divisional, then have one real game in the way to getting to the Super Bowl. I don't like their odds vs Seattle or (more likely) the Rams, but if there was ever a year for a less than fantastic AFC team to get to the Super Bowl, this is it.