It is tricky to measure
It is tricky to measure battery degradation. How did you do it? Because if you’re just looking at a little battery symbol on your screen and dividing the number of miles by the battery percent, you are way way off. Tesla will confirm this. This is a very very crude estimation tool. To be accurate the battery calibration would have to be perfect. And the battery calibration is nowhere near perfect. You will see in Youtube range tests by Bjorn Nyland and iothers - the accurate way is to drive your car from 100% to close to zero, and determine the number of kilowatt hours used by the battery pack. This is accurate. In these videos, the degradation determined is far different from what the screen shows. Basically that little battery symbol on your screen is useless. A good way to estimate degradation without driving the car all day from 100% down to zero is to get the Teslafi app, and look at kilowatt hours used for a long journey. The longer the better. Divide this number by the battery percentage used. That is your full remaining battery capacity in kwh. Compare that to the capacity when new(after deducting the buffer of about 3kwh) and that is your degradation. It’s OK to stop a few times during this journey, Teslafi will break it down. Then you just have to add the numbers up. My car for example, a 2020 SR plus, shows almost 10% degradation on the screen using the crude method, and about 3% degradation if I actually determine how many kilowatt hours are remaining in the battery using the aforementioned methods. It would be very interesting to see your comparison of the two cars after you ran the test this way. I suspect the degradation on your model Y is far less than you think.