You can't deny having a QB on their rookie deal helps.
AFC playoff teams with QBs on their rookie deal: Buffalo (Allen's extension money kicks in next season), Bengals, Jags, Chargers, Ravens, Dolphins. 6 out of 7 playoff teams have QBs on their rookie deal. Only team without a QB on his rookie deal is KC.
NFC playoff teams with QBs on their rookie deal: Philly, NYG Less so on the NFC with only 2 out of 7 teams with QBs on their rookie deals but when you dive deeper you'll see most of the NFC QBs don't have huge numbers.
I didn't count SF because they have Jimmy G although his cap hit is middle of the pack at $12.6M. Brady's cap hit was only $12M, Dak's cap hit this year is only $19.7M but his extension kicks in this season and his cap hit surges to $49M for 2023. Seattle has Geno Smith who has the 34th QB cap hit in the league. Only cousins truly has a huge cap hit among NFC playoff teams.