I did some testing. Put all 4 assistants as shortcut on main screen.
View attachment 23062
But, when I switched off ignition, left the car and came back 2 minutes later, all the shortcuts defaulted to start/stop. Also it takes some time to load main screen, so you can go to car menu on the meantime and just do it from there.
And here's video when I was switching off everything from car menu and you can see system had some glitch and went back to system settings for a moment.
If you need gateway car, something more simple might be better. You jump in and driveway without checking settings or waiting for screen to initialise.