My new Xs max doesnt have 1 year limited warranty

That's because you bought a gray market phone that is, by definition, used.

The warranty begins on the day the device is sold by Apple or an authorized retailer.

You did not buy it from an authorized retailer.

Every new phone does get a one year limited warranty that begins on the day it is sold.

The activation date has nothing to do with it.

You bought a used phone.

The warranty began the day it was sold by Apple or an authorized retailer.

You bought a USED phone.

Because the warranty starts on the day of initial purchase. You have purchased an iPhone that was discontinued in September 2019, and was initially purchased 6 months ago.

We are saying your iPhone was initially sold by Apple approximately 6 months ago. It was then re-sold by the dealer you purchased from.

Which means it was purchased as new. Your iPhone XS Max was not.

Nope. It has a one year warranty, that starts on the first day of purchase.

You’re welcome.