Reaching the AFC championship really helped Allen.

Since Josh Allen was drafted -

Cowboys are 54-37 (https://www.statmuse.com/nfl/ask/cowboys-record-since-2018)
Cowboys have 2 division titles (https://en.wikipedia.org/wiki/NFC_East#Division_champions) With a 2-3 playoff record and never been passed the Divisional round (https://www.pro-football-reference.com/teams/dal/playoffs.htm)

Bills are 58-33 (https://www.statmuse.com/nfl/ask/bills-record-since-2018) - Bills have played one more game than the Cowboys Bills have 3 division titles (https://en.wikipedia.org/wiki/AFC_East#Division_champions) With a 4-4 playoff record and one AFC Championship appearance (https://www.pro-football-reference.com/teams/buf/playoffs.htm)

I honestly expected there to be more of a gap but that shows what media perception around the Cowboys does