[S7E5] The huge hole in Cersei's logic

Near the beginning of "Eastwatch" Jamie confronts Cersei saying the war is unwinnable because the Dothraki and dragons are unbeatable.

Jamie: "I just saw the Dothraki fight. They'll beat any mercenary army. They'll beat any army I've ever seen. Killing our men wasn't war for them, it was sport. Her dragon burnt 1000 wagons, Qyburn's scorpion fired bolts bigger than you, they couldn't stop it... and she has three of them. This isn't a war we can win."

Then later in the episode Cersei suggests some sort of truce with Daenerys as a means to beat her. Hinting at a sort of Red Wedding betrayal like her father orchestrated.

Cersei: "I've come to believe that an accommodation with the Dragon Queen could be in our immediate interests. She has the numbers, if we want to beat her we need to be clever. We have to fight her like father would have."

Say hypothetically Cersei kills Daenerys. That takes care of none of the problems Jamie outlined making this war unwinnable. Congratulations you now have a leaderless Khalasar of 100,000 Dothraki roaming Westeros, a pissed off army of Unsullied and three motherless dragons. The only thing holding these forces back is Daenerys.

Killing off Daenerys in a Red Wedding style betrayal won't solve problems, it will create more.

Also looking back to the Red Wedding: in the long run it didn't work. All three of masterminds of it ended up dead, two of their houses are destroyed (Bolton & Freys) and the North is now back near the power it was before.

Cersei's logic seems to skewing more towards Joffrey, losing a grasp on the big picture for the smaller victory in front of her.