Black Friday Deals for.....EVERYONE?

Attempting to trade my S-21 for a "free" Pixel 7. The S-21 was "free" 20 months ago, (device pymt is offset with monthly credit). I have 10 of 30 payments left. Also, I elected "Next Up", and "Unlimited Elite " plan.

That is not how any service provider does its phone promotions. If you look at your bill you are receiving a credit against your installment every month. When you upgrade a line, cancel a line, your credits stop and you owe the remainder on the phone (10 payments) 

So, using the My ATT app, I selected "shop now" under Deals, I selected Pixel 7, but during the process, all I could get is $10.84 monthly device pymt,  not $0 monthly device pymt. 

Because your phone isn't paid off. 

So why have I made 20 $6 monthly payments for Next Up?

Ad indicates "new and existing" get for free.

I'm very confused.

Okay  "next up" allows you to upgrade early without paying off the remaining payments on your phone, you can then start a new installment at the regular retail cost.  Your next up device is required to be returned to AT&T in order to waive the remaining payments. It does not make you eligible for any of the trade-in deals because in order to take part in the trading deals you have to turn in a phone that is 100% paid off.  When you trade in a phone it goes to a third-party recycler in Tennessee called HYLA mobile.   You cannot return an early upgrade phone, that's not paid off, to AT&T and at the same time send it as a trade in to hyla in Tennessee (which is a completely separate company) 

It is now up to you to do the math.  Do you want to pay off the last 10 payments to trade in your Samsung phone, or do you want to forego those last 10 payments and pay full price for a new phone over 36 months.