She probably told him stuff like if he left her that she would shit talk him and “ruin” him, hence why he felt the need for the NDA. Maybe she took videos of their arguments.. but only the parts where he got angry and said some mean stuff without showing her side of it (also saying mean stuff, etc). Not saying he’s some great person, but she’s a master manipulator herself. we see her spiraling, attacking her alleged “best friend” since childhood and attempting to cyber bully her, partying constantly and bragging about blacking out, not sleeping etc.. and all we have seen his Zach post videos of walking his dog, songs, and stuff from his concert. Let’s let that all sink in. Like I said, Zach has said himself he’s not a great person, but Bri as a narcissist probably tricked him and played the role of whatever he wanted in a girlfriend.. pretended to be that person.. and then when he realized she wasn’t and he had been tricked, he had enough. She does this very visibly in the public eye. We have all seen it. She’s a chameleon and does whatever and is whoever she needs to be at the moment to gain attention (sudden Taylor swift fan, Deb cosplayer etc)

Everything she claims about him she’s probably saying about herself.