I don’t know, the word “dangerous” to me doesn’t really mean “best”. Like, a fighter is “dangerous” not because he’s the best, but because he’s got certain ability that can, if the stars align, instantly change the course of a fight against anyone, any time, anywhere.
To me, “dangerous” abilities for a defense are things like getting sacks and forcing turnovers. Things that can change the course of a game instantly. The Bills don’t do either at a super elite level.
I think the Bills are better described as a “methodical” defense. they play a more slow-burn, suffocating style in my opinion.
I’d call the Steelers more “dangerous”.