After checking around to make sure Samsung Galaxy S8 can be rooted on Pie, I bought a model SM-G950U phone, but discovered to my dismay that the bootloader on U.S. versions with Snapdragon processors is not unlockable (there is no "OEM unlocking" setting in Developer Options, and none of the tricks with changing the date or waiting 7 days for Prenormal RMM state to pass will work to make it show up). All the rooting instructions I've been able to find only work for international versions with Exynos processors, or require downgrading to Nougat.
Is there any solution available have model SM-G950U rooted and running Pie?
If not, would any of the international models that can be rooted on Pie (SM-G950F, SM-G950FD, SM-G950N) work with U.S. carriers without disadvantages in service? (I have AT&T and would prefer not to switch carriers unless I absolutely have to.)