Help with weird sound coming from front left

Hello. I have a 17 lexus is300 AWD V6. This sound came out of nowhere (videos below). I haven’t hit a curb, pothole, or anything similar. I took it to a shop and they couldn’t find anything in the suspension that was bad. They suspect it is the rotors and are telling me it’s going to be trial and error. The sound only comes out of the front left brakes, and the frequency of the sound intensifies related to speed when breaking. Only happens when breaking normally, I can’t hear it if i break hard. Any suggestions are appreciated before dropping $800 in a new set of breaks.

Videos: https://imgur.com/a/3juY7yR