Back peddling? Lessening his part in it all? Take your pick. Imo, BD was his own worst enemy. I don't agree with his lawyers actions. However, I do feel that if BD just co-operated and took a plea bargain, he would most probably be nearly finished his sentence now. He would have some hope for a future.
How would Dassey be lessening his role in the crime by saying for months he thought his uncle hadn't killed Halbach? If he was was there, watching it, participating in it and helping clean it up afterwards, how could he possibly think his uncle didn't do it?
All you need to do in order to figure out his "confessions" are made up is read them.
Fassbender: Where was her truck?
Brendan: Outside.
Fassbender: Alright. We know that's a lie. So where did he put her truck?
Brendan: In his garage?
Fassbender: That's better. Now you're telling the truth. Did he have the door open or shut?
Brendan: Open.
Fassbender: I can tell when you're lying and I don't like it.
Brendan: Closed.
...........
Fassbender: So after he shot her what did you guys do next?
Brendan: We carried her out and put her on the fire.
Fassbender: No. That doesn't make sense. We have evidence that suggests other stuff happened in that garage first. Something with the truck.
Brendan: After he shot her he put her in the truck for a second and then we put her on the fire.
Fassbender: That's better.
The icing on the cake?
Fassbender: Why did you tell us before that you cut her throat?
Brendan: I was guessing.
Fassbender: Why did you tell us you cut her hair?
Brendan: I was guessing.
Not "I was lying." Not "I was trying to come up with a story." He was trying to guess the correct answer that the investigators wanted to hear. If you believe his confessions are truthful, which parts do you believe? She was shot once? Twice? Ten? Five? Throat cut or not cut? Hair cut or not cut? Stabbed in the chest or not stabbed in the chest? That the fire didn't smell? That it did smell? That the fire burned for about an hour at which time Avery was already smashing up her bones? That he rode in the SUV to the pit or didn't ride along to the pit? That Avery hid the knife in the truck? That her shirt was blue, white or black? That Halbach did or didn't have pubic hair? That the murder was a random, last minute choice or a planned event from three days prior? That Halbach was naked when stabbed or had a shirt on that had a knife hole in it? That a creeper was used to move the body or they just carried her? That she was stabbed while sitting in the front of her SUV, in the bedroom or in the garage?
And which parts of his "confessions" do you believe have been backed up with independent physical evidence?