Every luxury vehicle I looked at had it or had a package that included it, including the 2023 Nautilus. In fact, I went back to the Lincoln site and low and behold, it is indeed part of a package for the 2023 but not an option on the 24.
I think you mean there is the "cargo accessories and mat package" which isn't very clear compared to the 2023 build. The 2024 build just says "All weather floor liner." If you build a 2023 model, the same package makes it abundantly clear it removes the carpet mats.
I blame Lincoln for not being clear. The website hasn't been great. The correct terminology is a "cargo cover." Some sites call it a "retractable cargo cover" or a "security shade" but the Ford and Lincoln websites list it as cargo cover. The thing that goes on the floor in the cargo area is a "cargo mat" or "cargo liner" or on this particular build (2024 nautilus) the "cargo area protector."
I'm guessing the 23 fits the 24 (Ford Part No.: FA1Z-5845440-AK) and will see what the dealer has when I pickup the vehicle. If not, Amazon. No doubt the Amazon ones come from the same place in China. I just know I will not put anything in the back without a cover. Otherwise, your car gets broken into.