You don’t need to worry about whether it’s relockable, but it’s important that it can be unlocked in the first place. Just don’t get it from a carrier and you’ll be fine. Buy the phone from some store like Best Buy.
The standard seems to be complete and utter garbage. It was garbage from the very beginning, which is why I never understood why people were getting so incredibly hyped up about RCS support.
You don’t need to worry about whether it’s relockable, but it’s important that it can be unlocked in the first place. Just don’t get it from a carrier and you’ll be fine. Buy the phone from some store like Best Buy.
To answer your second question: It uses USB-C.