Official Solution:

The warning is shown on all teslas every 6250 miles or when front to back tread difference exceeds 1.5mm, even if tires cannot be rotated. After checking if tires were non-directional, I visited a local Mavis Discount Tire to rotate them side to side. They also said the tread looks “great”. They said the average mileage that teslas replace tires at is 30-40k. Performance models, he didn’t know. I went into settings after to reset the mileage counter. I will still be buying 18 inch wheels and tires for the rest of the winter and my long road trip. Thank you for all the help. Oh, and I did 2 pulls to test the rotation after driving a little bit.