I wonder if that's really true, or if the claim is a legacy of the 3G networks, which are decommissioned now in the US. I got the Latin American Galaxy A56, which Amazon listings also say won't work with Verizon, but it actually does.
Just as it has done with previous Fairphone smartphones, Murena will sell the Fairphone 6 in the US. However, this version which will come with e/OS/ will not work with all US networks.