Alright, so I just replaced all 4 rotors and pads a few weeks ago thinking that was causing the squeal. While they needed to be done it hasn't completely gone away. The rear pads were pretty bad so it helped stop the squeal from happening all the time but it still does it while braking. I was also googling other solutions and came across things about the parking break. I had used it recently so thought maybe it was stuck since it's rust. I pushed it down and released it probably a dozen times at different pressures. Still didn't help. Here's a video of what it sounds like outside the car. Did 2 different takes, one that's a little harder braking. I am 99% sure it's coming from the rear drivers side wheel.
*edit* deleted the video from youtube since the problem has been fixed.