I purchased a Galaxy Note 20 Ultra from At&t. Subsequently I have been surprised at the discrepancy we US customers face and Samsung's abysmal customer support for customers of their flagship product.
The phone did not have a pre-installed screen protector. The At&t store people initially told me that it would have it, and then opened the package and told me that it did not - and that none of the Note 20 or Note 20 Ultra would have it. I ordered a few third party protective cases for the phone to find printed cards in them which said they do not include a screen protector since the phone comes preinstalled with one. When I contacted Samsung, the customer service (both the initial agent and his supervisor) told me that the Note 20 Ultra indeed should have the screen protector on, and that Samsung has no system in place to send a screen protector to a customer. Now I am being thrown from one court to another trying to find out what could be a solution since the phone does not play well with any available screen protectors in terms of the ultrasonic fingerprint detection. Am I supposed to believe that Samsung thinks that the US customers are gullible enough to use the phone without one while they harp about the newest Gorilla glass installed on the phone while they provide a screen protector for the rest of the world? Or is it that At&t is trying to dupe me with a faulty package here?
I also have issues regarding headphones and adapters which I will start a different thread on.
To answer your other question, No AT&T did not dupe you. Samsung does not provide screen protectors, replacement stylus (s pen) tips, or headphones in the box, as they have with previous devices. This is only true with US destined devices, other regions got all of these things, but samsung believes that we americans will throw all of this stuff away, or simply not use it. The cases you have purchased are likely international packaging, which is why they state that a protector is pre-installed.
The headphones can be requested free of charge though samsung support.