You are NOT the only one experiencing this! I think the lack of response is because this is just beginning to show up for many of us. I'm the owner of a '21 Plaid w/21's and have the exact same issue. Spent the early part of this week going through all the chaos of identifying the problem, trying to find replacement tires, and dealing with Tesla Service. All have been a nightmare!
My issue started with a low pressure warning which I thought was a simple nail puncture. Discount Tire was convenient and I had great luck with them for years so this was my first stop. Imagine my surprise when I found the entire inside tire worn and delaminated. I cautiously (perhaps stupidly) made it home and had Tesla Roadside pick up the car (I'll spare the frustration of trying to have someone, anyone at Tesla be able to tell me if they had a tire in stock before it was towed....aaargh!). The rest of the story is are as yours....pound sand, we don't warranty tires. Luckily they had one tire and managed to find another so both of my rears are replaced. I thought it was only one side, but turned out to be both.
TLDR..... 2021 Plaid, 21" Arachnids, 100% stock, 13k miles, two demolished rear tires with even wear except extreme inside edge, no support from Tesla.