To properly ground my vehicle, I make sure the wheels are touching the earth (at least 3 of them).
(Yes I am poking fun at the questioning of grounding continuity/effectiveness regarding aluminum and composite structures)
It was more of pondering out loud.
I know combining steel and aluminum in structures
can result in galvanic corrosion. But aluminum combined with steel has been used in vehicles for quite a while. Land Rover started in the 1940s. Jaguar for at least a decade. I believe it is common on 18 wheeler trailers as well.