Really isn't that much different from an ICE car in this regard - once you have some experience.Is there a time frame/mileage when tesla 12v battery fail? A failing 12v battery on a tesla is more inconvenient than a regular ICE car. It would seem to be smart preventative maintenance.
Jumper pack & the car will start and the DC2DC will provide the needed power. Unless the battery is so bad that the jumper cannot get it going. In that case, disconnect & replace the 12v.
I believe it will also run with the 12v out, once it's going. Just don't let anything short out!
Use the climate keeper mode to keep the car from sleeping so the DC2DC stays active after it's jumped.