Deck belt flopping like a fish on new zero turn

[dis360]

Just purchased a new Troy bilt Mustang Z 42 zero turn little over a week ago, got it home performed the initial set up, checked everything, started it up and drove it around the yard for about 30 minutes. Runs and drives very smooth and quiet, before putting it away I decided, I would check how smooth the deck is on a brand new mower, I have a Troy bilt Bronco made in 2013 to compare it against, as soon as I engage the electric PTO, waited for the blades to spin up, I said to myself that’s not a smooth running deck, it’s bouncing up and down and left and right, I gotta look at the belt and you can see that it’s just flapping around too much moving the idler pulley too much, moving the tension spring back and forth, it creates almost like a low frequency oscillating vibration, the belt is flapping a lot of between the deck and the electric PTO in the rear and just all around the idler pulley on the deck. I decided to check everything I could, checked every single idler pulley, blade spindle and all the bearings. Everything‘s tight normal nothing‘s bent, checked that the blades aren’t bent or missing any pieces. They look fine checked the non-adjustable tension spring, it’s got plenty tension on it. I checked the rear pulley on the engine, looks good, nothing stuck inside any of the pulleys. I took the belt off checked for defects and if it is the correct model, looks good. Kinda out of options here, I called Troy bilt and explained the issue. They want me to go about an hour away to the closest warranty service center which is really difficult, I don’t have a truck or a trailer. I’m hoping someone might have an idea of what I can do. I was really planning on uploading a short clip of the vibration as it’s very obvious , I will have to figure out how and update the post.

Video 1: https://drive.google.com/file/d/1DloK2Z6yVZ7zyvbMRWHp7fkM9pydfZea/view?usp=drive_link

Video 2:https://drive.google.com/file/d/1r5L-5WLmASNysDZkZ-EX2E-bp3LZ7AhX/view?usp=drive_link