As I understand it, the US is mostly waiting for UL listing of equipment, which hasn't been a priority because no US locals have allowed them. With Utah and others starting to allow them, UL listing will likely come at some point (hopefully shortly) thereafter.

There's this device: https://usa.apsystems.com/ez1-installers/

And also this: https://connectder.com/

State plug in solar legislation tracker: https://www.brightsaver.org/legislation-tracker

(passed in 10 states, 2 awaiting signatures, as of this comment)