Secondary sim card on xfinity financed device

Hi,

I am planning to buy an Apple iPhone 15 with Xfinity Mobile on a finance plan. Will this allow me to activate another secondary eSIM card on the Xfinity-financed device provided that the device is not paid in full?

• Line 1: Xfinity Mobile
• Line 2: T-Mobile, Airtel or AT&T (primarily for international travel)

I am sure if the device is unlocked then I can add as many lines as the phone supports. Will Xfinity Mobile allow a secondary line along with it?

I can pay the full amount to get unlocked but the promotion credits stop. So, I am stuck. I cannot take a phone that serves my purpose.