As long as EFILive has direct access to the ECM CAN bus then yes the unlock will work on 2018's.
I don't know the specifics of the bypass solution presented above but essentially you are just wanting to connect to the CAN bus AFTER the Gateway module, if the bypass unlocks the module to allow additional OBD-II messages through then it might not still work (like the TIPM in the 2007-2012 is an issue as it does not pass-through all messages required for unlocking).
I don't know if the plugs are suitable for the Ram but this seems like a better solution.
https://zautomotive.com/product/double-bypass/