Question s5 region lock in USA ?

Hi,
I read that to get rid of region lock in European Model, Galaxy S5 customers need not only to activate, but also make a cumulative calls over 5 minutes in their region before transferring and using it overseas carriers. (there is Network Lock or carrier locked or only region lock?)

but the Big Q are about the models in the USA how to fully unlocked "activated" (Network Lock or carrier locked)
and unlocked the region lock if there is any?

if in the US it's only carrier locked there is an app for that without root or only pay to some website? (any Recommended website?)
with and without rooting the device becasue the KNOX probleam?

there is root for S5 without active the flag to "1" in the knox ?

thank you!