u/Disney_freak8

I’ve never posted here but I’m hoping someone could provide some insight. I drive a 2012 Lexus RX350, just over 100,000 miles on it. In November 2025 I got both rear brake pads and rotors replaced. A few weeks ago, I got my tires rotated and balanced at Discount Tire.
Last week I started noticing a faint squealing noise when my tire rotated, and at the same time heard a faint rattling noise near what sounded like my back seat passenger side floorboard. I assumed the rattling was something in my trunk moving around and it would stop at times when I would rearrange things in the back, but would usually come back.
The past 2 days I’ve noticed the rattling and squealing get worse. This morning was the loudest it’s been. It was noticeable yesterday morning but not yesterday evening though. All of my googling has come back with different possibilities so I have no clue what to think. My mechanic is closed on the weekend, they close right when I would be able to get to them after work today, and I am supposed to drive a 6 hour trip next week, so I’m feeling pretty helpless.
I have attached a video I took while driving this morning of the sound. It seems loudest when I am either driving slow or 60+, but it’s not as noticeable with the speeds in between. Could anyone possibly provide any insight? I will do my best to answer any other questions, I’m not very car savvy but I will try! Thanks!