Tire question 2024 Crosstrek premium

Saturday I had the unfortunate incident of a flat. I put the donut on and knew immediately the tire could not be repaired. I have an extra warranty on tires and wheels. I went to the dealership today. They replaced the damaged tire with a new one. My concern is the tread difference. I was hoping they would put a tire on with similar wear. I have about 43,000 miles on the other three tires. There’s a tread difference of 1/8th inch between the one new tire and the others. I ask the service manager if that tread difference would pose an issue. He said “nah it will be fine.” Everywhere I have read, this is very bad for an AWD.

Is there something I should do? I don’t want to start having mechanical issues due to this?