Surely you can just do that from your phone using the google speech icon connected via android auto for example and is nothing specfic to just the Megane using hive or or another app.
my whole home is basically smart, from blinds to every switch in the house almost, smart plugs etch have a setting in them to auto back to on when there is a power cut, but the system I run is all run locally apart from my alexa speakers everything is local.
one thing I do have as an advantage though, is I am on a go tarrif with a cost of 12p kwh for 12:30 to 5:30am and lucky enough when I was still able to work I put solar in with a 6kwh battery, I actually dont charge the battery at all from the solar and set it to charge from the grid during the cheap off peak times (as well as car) so for the next day I probably use 1 or 2 kwh… I am currently campaining to the govt that people that are in a situation were at times they rely on connected equipment, (stair lifts, home monitoring such as telecare etc) should be automatically given a grant for solar and a battery… not only will it be benificial for them, it could also be a life saver if there are power cuts.