Transfer switches are trivial to have installed. I already have a manual, interlocked one for a portable generator.

I have a 13kW array on the roof and live in a place where ice storms make power outages a thing most years. My solar inverter is grid following. Even if I can't get grid forming from a car I'd only have to pay for a small battery and grid forming inverter to cold start the whole operation rather than $10K of extra batteries for them to do the grid forming. Then I can let the solar and vehicle do their thing and follow the islanded grid during the outage.